I'd suggest not to pay FP for the Stress Test.
My reasons: I did it for the first Stress Test, and ended up paying around 21$ due to, the first time I signed up, it seemed to not process correctly, so I thought maybe I couldn't get it with the 6$ account, therefore I downloaded the 15$ one, then, found out that since I had tried earlier before I payed money to get into the Stress Test, that I had got a Stress Test key in my Gmail, then, upon trying to cancel the damn FP accounts, we contacted their customer support, technical support, it was a living hell.
Just today I got two emails about "Account Cancelation"...
When did the stress test end again o.O?