Figure what its worth to you for a beater. I love my 240d however it needs a paint job, if I did that and had to sell maybe I would breakeven. I have seen extreemly nice one's on ebay go for $3200-6000. I'm talking nice original paint, maintenace history some with 60 thousand mile. Snowbirds in Florida use them in the winter when they comedown for a few months every year. The they get too old to drive and let it go. I always thought the most expensive work was the body and inteior. The engine and stuff at least I could give a try but body work and I have no comman thread. If you don't mind driving a beater and I'm not to proud, give it a shot as long as you have some time and its cheap.
There will be some satifaction when you get it going. Just don't expect a show car and its ok. Good luck and have fun.