I use one with an external sound card interface by ZLP Electronics. It works fine on FT8, Fldigi, etc. The only half decent logging program is CQRLOG, but that’s very poor compared to the log programs available for Windows.
As to spare parts, what parts does a Pi need? The cases and power supplies are cheap as chips new. However the best value computing has to be an old Windows XP laptop, they are only good for scrap value and can often be scrounged for nothing, or perhaps a bottle of wine.
73 Dave