DraStic

Let's get to the point; in Euros, the price for DraStic is 4.49. In USD, it's 5.99 (which takes an absurdly long time to save up to if you use Google Opinion Rewards), while, if you convert EUR to USD, it should be 4.82 dollars. So basically, you're being scammed of 1.17 dollars if you bought this with USD.

And then people are complaining about this app being pirated...

Exchange rates change over time, USD was a lot weaker vs the Euro before and the prices aren't being regularly changed to reflect that. It's not a deliberate attempt to charge European people more than American people.

Get a job. Problem solved.