Just curious as to why you would come here for help.
This is where to go for assistance in -FIXING- machines, not FINDING.
I would suggest you do google, yahoo, Etc searches 'for sale' and what you want.
HEF is very much the place to ask which machine to look for or stay away from.
There are a lot of members including myself that have O&O experience on all sorts of machines knowing the good, the bad and the ugly. The last thing I am is a mechanic..
Now to answer Brandon's question with another question - What do you need the excavator to do? This will begin the discussion on the size machine you need. Price is a variable of size, location (for shipping cost) and condition.
I've owned two Cat 315's - one C and one D - both were excellent machines as heymccall stated.
Also owned a 325DL which was probably the best hoe we've ever owned. Strong, fast and well balanced. Had zero problems other than the Great Recession of 2009 that forced it's sale.
Currently own a 321DLCR with close to 7K hours on it which has been a great hoe. The largest $$ repair other than wear items was a boom solenoid.
Also currently own a 325FL '18 model with 1800 HRS that has had more problems than any one single Cat hoe I've ever owned, might have had more problems than all the hoes above combined but can't say for sure as the memory fades over time.
There is a lot more to discuss about dealers, parts availability and so on so give us a little more information.