Handheld Linux Retrogaming recommendation? [solved-ish]

I figure it will be a good thing to throw onto a wish list for whatever holiday is coming next. In a perfect world, it would run a Linux-based OS, be moddable, have decent ergonomics for an adult, and kinda just generally not suck. Is a hundred bucks a reasonable price point? One hundred fifty? I grew up in the 8-bit and 16-bit...