Hi, I also feel cheated by Affinity in the same matter. I just received an e-mail stating "We hope you’ve enjoyed exploring the powerful tools Affinity Designer has to offer. Although your free trial has now come to an end, you can pick up straight where you left off and continue to produce high quality artwork for only US$39.99 " which is just a cheating to get you to the checkout where you see completely different price. The price for me is 239.99 PLN which is 64.57 USD (!) or even in EUR this is still 56.62 UER (not 39.99 EUR).
In my opinion this is not even legally binding cause I received an official offer and it should be honoured and apparently it is not. However I see I'm not the only one treated this way hoping that the customer will just "click" and "live with the little lie".