I'm pretty much in the same boat as you Mert. Been using goggles over prescription glasses for the most part, but I like the convenience of regular sunglasses. Problem is my presc. eyeglasses cause my eyes to water something fierce at anything over 40 mph. The goggles over glasses isn't all that confortable, but it's cheap and I'm all over cheap.
My big problem with RX compatible biker frames is my sphere and cyinder numbers aren't user friendly for that application. A -3.25 sphere in the left eye, and a -4.00 cylinder in both eyes makes it hard to find a pair of wrap arounds that work. I checked out that riderseyewear.com and although the frame prices are great, their prescription lens charge of $99 for clear and $110 for tinted seems a bit excessive.
So after all my searching, I'm thinking of just going with contacts and some cheap biker wrap arounds. Problem is I've never had contacts so I don't know how I'll take to those. At least I won't spend $250 for a pair of riding glasses that I might not like.
Being blind sure ain't cheap, is it?