If you live in an area they cover, check Craigslist. You should be able to get a used PC better than you had for about $25- $50. If not, try Goodwill. People dump older PCs all the time. They basically have no value.
If you are really down to tyring to find a used PC for $25-$50, the I personally would just try to replace teh sound card. It’s a lot less of a headache than inheriting the problems of some old, used, unknown PC, and trying to configure the operating system how you like it and re-load all the software you like. Sound cards are easy to replace on most PCs. Remove cover, identify old sound card, remove from slot, plug new card into slot, replace cover, and plug in speakers.