I recently bought a '94 850 but have been noticing that the locks are sticking. On the drivers side door, the key won't even go in the lock fully and on the passengers side the lock goes in but won't turn. The problem has been getting worse, so as of right now, to lock and unlock the car I must go from the trunk which is somewhat inconvenient...The key FOB also doesn't work, I've replaced the batteries in it several times. Any tips on how to fix this?

 

New lock cylinders for both front doors (about $100 a piece from dealer) and maybe more stuff beyond that. Have you tried lubing the locks cyls?

Do the locks work by pushing/pulling the inside buttons? If so, maybe lock cylinders is all you need.

 

I'd use a "straw" on the end of an aerosol can to try and spray a liberal amount of a penetrating oil into the locks. Something better than WD40, something that's an oil and give it some time to soak in.
If you can work the locks with the ***** on the inside of the doors than it's likely just the door key locks themselves.

Take the transmitter to an Autozone, Oreilly or ..... and have it tested (free) to see if its sending out a signal. If you're lucky it's a bad transmitter. If not, maybe a blown fuse in the car or a bad receiver. The receiver is behind the glove box mounted on the fender side.