Hi. I'm 10th level and running low on cash. I've mostly been doing faction quests which don't result in much gold. Where is a good place to acquire gold? I know there are several bandit caves. Is this a good place to start? I don't want to do anything illegal. So far my only crime has been trying to sleep in someone else's bed.

clearing out bandit caves is considered a public service and is quite virtuous in Morrowind. you even get to free some slaves sometimes.
I would definately recommend going bandit cave spelunking.

How does one tell the difference between a bandit cave and a quest tomb....I hate to get in over my head......

easy, if you come across an item that got a person name in it eg. "stcardgeek's ring of destruction". then it's probably quest item. ;)

ok for lots of money fairly fast and close to town hit up the islands east of vivec there are 2 really nice theifs caves as well as i believe 3 sunken ships.