> I took this approach with a refurbished i5 Compaq off Newegg and I had the same
> intentions. Today that machine has 20g of Ram, Win 10 and a video card. I am guessing
> I put another $65-$75 into it but now it plays everything.
Yeah, that's pretty much the way to go. The general MAME dev suggestion is any relatively recent i5, a decent amount of RAM so that Windows doesn't pitch a fit, and if you want to run with shaders enabled (which OP probably doesn't due to having a proper CRT), a half-decent graphics card.
Nothing even approaching top-of-the-line is necessary. There's a huge performance gulf between "games that are playable on halfway-modern PCs" and "games that require more horsepower than a PC will likely ever have", so optimize for the former and not the latter. Nevertheless, it's important to not buy some worthless shit-box of a machine like a Raspberry Pi or a Core 2 Duo either.