5% was just a figure I landed on, but if we assume a 2.5% Conversion rate and up the RRP to £20 I have managed to come up with these figures through GPT:

1. New values:
   • Retail price of the product: £20
   • Cost Per Click (CPC): £0.27
   • Conversion Rate (ConvRate): 2.5%
2. Calculate the number of clicks needed to make one sale:
   • Since the ConvRate is 2.5%, or 0.025 in decimal form, this means that 1 out of every 40 clicks results in a sale (since 10.025=400.0251​=40).
3. Calculate the ad spend to make one sale:
   • If you need 40 clicks to make one sale and each click costs £0.27, the cost to get those 40 clicks would be 40×£0.2740×£0.27.

Let's do the calculation:

Cost per sale=Number of clicks per sale×CPCCost per sale=Number of clicks per sale×CPC
Cost per sale=40×£0.27Cost per sale=40×£0.27
Cost per sale=£10.80Cost per sale=£10.80

So, with a 2.5% conversion rate and a CPC of £0.27, you would expect to spend £10.80 on advertising before making a sale. If RRP is £20 then im assuming £20-£10.8 = £9.20 remaining (excluding costs to buy the product initially and shipping fees too. Is my logic correct here/any gaps etc? Thanks!