1993 Saturn SL1 My car won't shift or stay in gear

Transmission problem
1993 Saturn SL1 4 cyl Manual 174000 miles

I was driving my car and everything. I stopped at a red a red light, but when the light turned green I couldn't put my car into 1st gear - no gear really. I played around with it and I think I got it into 4th gear - the only way I managed to drive home was because I didn't have to stop or slow down. The whole gear shift is wobbly & won't stay in any gear - what could it be? And if it's a part, can I go with a salvaged one if I can find it? Thanks for any info or advice you may have