I setteled on this Windows PC stick: Building a pocketable X86 handheld "gaming" PC - #38 by TeckMonster
This screen (I’d still use this screen if I built one today): Building a pocketable X86 handheld "gaming" PC - #37 by TeckMonster
This battery (sorry, I guess I didn’t share the source for it): Building a pocketable X86 handheld "gaming" PC - #43 by TeckMonster
And a few little odds and ends like speakers, amplifier, thumb sticks, and arduino nano for controller inputs.
I never kept track of this, but I would estimate $1,500. I bought a lot of mini & stick PCs & screens. The cost is certainly put into R&D.
If you do deside to build one, @ me. I’d love to follow your build.
I’m currently working on outfitting my off grid property for living (literally just started this though): Tek's Advanced Off Grid Land [planing stage] - #3 by TeckMonster