Slowly buying up tools as i want to get into the trade one day, where is a good place for used tools (barrel vise, action wrench, used lathe, etc...)
Guntech about covered it in a nutshell.
For strictly gun related tools, if you want used, head for every gun show for a couple hours drive around, take cash, and know what you are willing to pay.
Then, after you have spent a couple dozen days, and several hundreds of dollars on gas and food to come up empty handed, order a Brownells catalog, and the prices don't look too bad all of a sudden.
Lathes? Kijiji, Craigslist, and about a thousand places online that advertise machine tools.
Order a KBC Tools catalog. Pretty much as close to a machine shop Christmas Wish Book as there is. It will give you a good reference for what is out there in the way of drills and measuring equipment, as well as some idea what they retail for.
Don't buy tools you think you need, buy the stuff that you have a use for, else you end up with a bin full of tools that have never been used.
Cheers
Trev