£18 for ChatGPT or £11 for five AI models: the real cost breakdown for UK stores

What you actually pay: the line-by-line comparison

I sell candles and home fragrance on Shopify. I also run an eBay store for the same products, and I post three times a week on Instagram because that's where half my orders start. Every week I write product descriptions, answer customer emails, draft captions, and rewrite listings when something isn't selling. I'd been using ChatGPT Plus for eight months, paying £18 a month, until I sat down one evening in January and worked out what I was actually spending.

ChatGPT Plus costs $20 in the US. In the UK that's £18 including VAT. You get GPT-4o, unlimited messages (with a soft cap that kicks in during peak hours), and DALL·E for product images. It's one model, one subscription, no hidden extras unless you start using the API.

Kryotta costs £11 a month for the Pro plan. That's about $14, or €13 if you're invoicing in euros. You get Claude Sonnet 4.5, Gemini Pro and Flash, Llama 3.3 70B, Mistral Large, DeepSeek V3 and R1, two GPT-OSS models, and three Amazon Nova models. You also get Stable Image Core and SD 3.5 Large for product photos, plus Nova Reel and Luma Ray 2 if you're making Reels or TikToks. All of that in one workspace, no API bills, no per-token pricing unless you're generating video at scale.

Here's the table I made when I was deciding:

The difference is £7 a month, or £84 a year. That's one less Boxing Day ad spend, or two months of Royal Mail Click & Drop credits.

When ChatGPT Plus makes sense: you want one model and nothing else

I'm not here to say ChatGPT is bad. It's not. If you only write customer emails and Instagram captions, and you've learned exactly how to prompt GPT-4o so it sounds like you, then £18 a month is a reasonable price for not having to think about which model to use.

ChatGPT also has the cleanest interface. You open the app, type, hit send. There's no model dropdown, no compare mode, no decisions. That's worth something if you're juggling three Shopify orders, two eBay messages and a crying toddler at the same time.

And if you're already paying for ChatGPT Plus because you use it for non-business tasks—homework help, recipe ideas, travel planning—then the business use is essentially free. You're not adding a second subscription.

But the single-model limit starts to hurt as soon as you need to do more than one type of task. GPT-4o is good at friendly, conversational copy. It's less good at terse product descriptions, technical spec sheets, or formal refund emails. I found myself rewriting half the outputs because the tone was wrong, or the structure didn't match eBay's character limits, or it added a cheerful emoji to a message about a delayed parcel.

And DALL·E is fine for Instagram story backgrounds, but it struggles with product photos that need to look like they were shot on a white backdrop. I tried generating images of candles in glass jars. Every single one had a weird reflection or a slightly melted edge. I ended up using my phone camera instead.

Where Kryotta saves money: multiple models, no API bill, and compare mode

I switched to Kryotta in February because I needed more than one model and I didn't want to pay for three separate subscriptions. Here's what I use each model for:

Claude Sonnet 4.5 writes my customer emails. It's formal without being stiff, and it handles refund requests and delivery complaints better than any other model I've tested. It also writes product descriptions that match the tone of my brand—warm, specific, not overly salesy.

Gemini Flash rewrites my eBay listings. It's fast, it stays under the character limit, and it doesn't add unnecessary adjectives. I paste in the Shopify description, tell it to cut 30%, and it gives me a clean eBay version in about eight seconds.

DeepSeek V3 drafts my Instagram captions. It's better at casual, chatty copy than Claude, and it doesn't try to insert hashtags unless I ask. I usually run the same prompt through DeepSeek and Gemini Flash, then pick whichever one sounds more like something I'd actually say.

Stable Image Core generates product photos when I need a specific background or lighting setup that I can't shoot at home. It's not perfect—sometimes the candle wick is in the wrong place—but it's faster than booking a photographer for £120 and waiting three days for the files.

The compare mode is what sold me. I can run the same prompt through three models at once, see the outputs side-by-side, and pick the best one. That's saved me hours of rewriting, because I'm not stuck with one model's interpretation of "write a friendly refund email that doesn't sound like a chatbot."

And I've never hit a usage cap. Kryotta's fair-use limits are high enough that I've never had a message bounce or a model go unavailable during peak hours. ChatGPT Plus has a soft cap—you get a message saying "GPT-4o is at capacity, try again in an hour"—and that's happened to me four times, always when I was in the middle of writing a batch of emails.

The hidden cost: API bills if you automate

If you're only using ChatGPT through the web interface, you'll never see an API bill. But the moment you want to automate anything—generate fifty product descriptions from a CSV, write a hundred email responses from a Shopify export, or batch-process images—you need to use the OpenAI API, and that's pay-as-you-go.

GPT-4o costs $2.50 per million input tokens and $10 per million output tokens. That sounds cheap until you run the numbers. Generating 100 product descriptions of about 150 words each costs roughly £1.80 in API fees. Do that twice a month and you've added £3.60 to your £18 subscription. Do it weekly and you're spending an extra £15 a month.

Kryotta includes API-level access in the Pro plan up to fair-use limits, which for most small Shopify and eBay sellers means you'll never pay extra. I've generated 200 product descriptions in a month and never seen an overage charge. If you do hit the limit, Kryotta emails you before charging anything, and the overage rate is lower than OpenAI's because you're using models like DeepSeek and Gemini Flash that cost less per token.

When to switch, and when to stay put

Here's my verdict after three months on Kryotta and eight months before that on ChatGPT Plus:

Stick with ChatGPT Plus if:

• You only write one type of content (emails, or captions, or descriptions) and GPT-4o already does it well.
• You use ChatGPT for personal tasks and the business use is a bonus.
• You hate making decisions and you want one model that's good enough for everything.

Switch to Kryotta if:

• You write more than one type of content and you're rewriting half the outputs because the tone or structure is wrong.
• You need product images or video and you don't want to pay for Midjourney or Runway on top of ChatGPT.
• You're automating anything and you don't want to track API usage or get a surprise bill.
• You want to compare models side-by-side and pick the best output, not the only output.

I'm saving £7 a month, which is £84 a year. That's not life-changing money, but it's enough to cover a month of Instagram ads or three months of Shopify's email marketing add-on. And I'm getting better outputs because I'm using the right model for each task, not forcing one model to do everything.

The other benefit I didn't expect: I've stopped second-guessing myself. When I was on ChatGPT Plus, I'd rewrite an email three times because I wasn't sure if GPT-4o had nailed the tone. Now I run the prompt through Claude and Gemini, pick the better one, and move on. That's saved me more time than the £7 saved me money.

Questions people ask

Does Kryotta charge VAT on top of the £11, or is that the final price?
£11 is the final price including VAT. If you're invoicing a business in Ireland or Northern Ireland, VAT is handled automatically depending on whether you're registered for VAT yourself. Sole traders under the VAT threshold pay £11, full stop.

Can I use Kryotta's models through Shopify or eBay directly, or do I have to copy-paste?
You copy-paste for now, or you use Kryotta's API if you're automating bulk tasks. There's a Gmail connector if you're answering customer emails through Google Workspace, but no native Shopify or eBay plugin yet.

What happens if I go over the fair-use limits?
Kryotta emails you before charging anything. The overage rate is lower than OpenAI's API pricing because you're using cheaper models like DeepSeek and Gemini Flash. Most Shopify and eBay sellers never hit the limit unless they're generating thousands of descriptions a month.

Is there a free trial, or do I have to pay £11 upfront?
There's a free tier with limited messages per month. It's enough to test the models and see if the outputs are better than what you're getting from ChatGPT. If you like it, you upgrade to Pro.

I'm three months into Kryotta and I haven't looked back. If you're spending £18 a month on ChatGPT and you're rewriting half the outputs, or you're paying for Midjourney or Runway on top, try the free tier at Kryotta and run the same prompt through three models. You'll know in ten minutes whether the extra £7 saving and the model choice are worth switching for.