Hey Jshopes81, I am in similar situation as you, renting not really and option depending on work that needs to be done, your day job, and everything else. For me as well, cheaper to buy and old machine that to rent a new one at $1500+ per week.
Bottom line, you can pay 5K,10K OR 30K they will all leak and will eventually cost you repairs at some point.Try and get a read on the owner for BS, ask as many questions as you can, test it as much as possible before you buy.
Rule of thumb that I always go by for and old tractor, if the engine doesn't knock and the hydraulics work, and last but not least, if the wheels spin when you push dirt, then you should be ok.
Its kind of a leap of faith anyways, so just make the best of it.
I am a hardcore John Deere guy, but if you want to get a 5K machine, in my opinion JI Case had the edge on Backhoes over any manufacturer from the 60's to the early 80's. Then CAT and John Deere caught up and the rest is history.
(Old MF's not bad either in those days with the Perkins.)
i just purchased a 1968 Case 580ck and as Tinkerer said, you will find a wealth of info on this site. Only a few weeks as a member and already had a bunch of questions answered. Good luck man.