take a look at combat arms
admittedly it's a decent game with a stuffload of guns and equipment which adds to the fun
but so many of those are not only pay2win OP but pretty expensive
buying a permanent assault rifle (in NX) literally costs $25
and even worse, they offered a crate once which would award a random "Epic" permanent weapon for the NX equivalent of $100.
that's ridiculous
but one could argue that surveys could be done instead, right?
bullstuff, 90% of surveys install adware, are scams, are shady and purposely unclear, and/or don't even work at all and try to coerce you with ads.
and "donating" is no different when you get unfair benefits for it no matter how little you pay or how small the benefit is if it gives you a noticeable advantage over other players in gameplay
go ahead and give paying players unfair advantages, but realize it's really not the right thing to do.