Reddit mentions of Sega Portable 2.8-Inch LCD Player with 100 Built In Sega Genesis Games with SD Slot (Blue+Black)

Over at Dingoonity a little while back, we were talking about some ultra cheap handhelds...

http://boards.dingoonity.org/other-game-systems/d-cat-16-bit-handheld-console-only-$11-99-on-amazon-and-has-a-sd-card-slot!/

The particular one I mentioned only plays Genesis ROMS, but there's a similar one:
https://www.amazon.com/Sega-Portable-2-8-Inch-Player-Built-Genesis/dp/B00F1P0TMS/185-6560902-7358833?ie=UTF8&*Version*=1&*entries*=0

And another user chip confirmed that it has undocumented ability to play other systems such as NES, SNES, Gameboy, and GBA. Though I wouldn't expect the performance of the SNES or GBA to be perfect.

Also the screens aren't that great and if you're trying to use it outside it might be frustrating. But, with that being said, for something that costs as much as a nice hamburger, it's worth at least checking out if at least for giggles :)

Other than that, I think something like GBA or GB Micro would be good, or possibly one of those random chinese devices like this:

https://www.amazon.com/dp/B01EA8H3RA/ref=wl_it_dp_o_pC_nS_ttl?_encoding=UTF8&colid=2QUV44IATOJS2&coliid=IZP2U9A6PT99T

or this:

https://www.amazon.com/dp/B01EAFHVTS/ref=wl_it_dp_o_pC_nS_ttl?_encoding=UTF8&colid=2QUV44IATOJS2&coliid=I14IVDECRPEZGV

or this:

https://www.amazon.com/dp/B01E9VIQL0/ref=wl_it_dp_o_pC_nS_ttl?_encoding=UTF8&colid=2QUV44IATOJS2&coliid=I1LZODW4GS2AFN

or this:

https://www.amazon.com/dp/B01B6FXTH8/ref=wl_it_dp_o_pC_nS_ttl?_encoding=UTF8&colid=2QUV44IATOJS2&coliid=I2DHEXSL3FR3AJ

(Just pulled those off my amazon wishlist)

But, I don't have any actual experience with any of those so I can't speak for the quality of them.

Hope that helps and good luck in your high tower gaming!!!