Best place to find a Gameboy Advance SP?

I used to have one of these and I loved it, but was stolen at school decades ago. Now I'm an adult, and I'd like to grab one and a few nostalgic games. I did look at buying a sealed one ($4,000? Yikes), so my initial question now branches into a few more questions:

-Are there reputable refurbishment shops? Specifically I mean deep cleaning, replacing the tape under the screen, etc. I don't mean Anbernic's 3rd party stuff, or after market cases that apparently do not perform well. I'm perfectly happy with an original, I just don't want to deal with 20 years of 'who knows where this came from' grime.

-Are there groups that might offer a cheaper one? I presume there were limited editions and normal releases. I just had a silver one, I don't think it was anything special.

-Recommended games? I had a Metroid game of some sort... Donkey Kong Country.... a few others I can't quite remember. My goal is about 12 games or so.

-I was today years old when I learned that there are fake GBA games and fake GBA handhelds.... how do you tell the difference, especially online?

Any help is appreciated. Looking forward to the maddeningly challenging minecart DKC level again!