It depends quite a bit on what era of machines you want to emulate. Last year I upgraded the PC in my high-end custom MAME cabinet to one of these (https://supp

It depends quite a bit on what era of machines you want to emulate. Last year I upgraded the PC in my high-end custom MAME cabinet to one of these (https://support.hp.com/us-en/product/hp-prodesk-600-g1-small-form-factor-pc/5387447/document/c03846648 https://support.hp.com/us-en/product/hp-prodesk-600-g1-small...) which I purchased on Ebay for around $100. I added a circa 2014-15 Radeon HD3850 I had laying around because it has native analog component output on a VGA connector to drive my 27 inch Wells-Gardner multi-scan arcade CRT (that analog authenticity is sweet perfection). Because that PC happens to be low-profile, I had to hack some metal out of the internal cage to get a full size graphics card to fit but there are tons of similar HP, Dell and Lenovo enterprise desktops being recycled on EBay so just find one that suits your budget and matches whatever stuff you already have sitting unused in your recycled PC parts bin (RAM, HD/SSD, GFX). One of the bonus joys of emulation is achieving something so cool and crazy fun out of free (or dirt cheap) recycled and thrift-store grade parts. The PC I got on Ebay will emulate virtually any arcade machine of the 80s or 90s. It can also emulate 8 and 16 bit home consoles and even quite a bit of the PS1 and Gamecube libraries. Our family and friends have so much fun with that MAME cabinet that, frankly, we'd pay for a new top-shelf PC for it but for the games we enjoy, there's no reason to pay for more expensive hardware. Also, be sure to hit the tip jar of whatever open source projects you use.