That was my thinking try and sell it for parts.
Would i need one if i try to build an amp?
You can go a long way taking DC measurements however there's some problems which are really hard to solve without a CRO. One is oscillation. If an amp oscillates you can see it quite clearly on the CRO. Without a CRO you have to use a lot of guess work and tinkering; even then with dubious results.
It is possible to use a sound card but it's usually not good enough to solve oscillation problems. The devices PRR mentioned very early in this thread are quite cheap and are probably good enough to get by. Yet another option is second hand stuff but then you don't always come out on top. Like your current case.
