What computer are you using? Most modern MBs from past 20 years or more use onboard audio.
So, I imagine it would be more about seeing what is available to buy second-hand online, at flea markets and garage sales and such. You don't need anything fancy for MAME, look for something Soundblaster 16 compatible, easier to find drivers. Think I've got a box of old sound cards somewhere.
If you find a Gravis Ultra Sound or an AWE32/64, they are worth a lot of money these days.