$13,500 really isn't enough to fish in the pond, though you might find a hidden gem in a barn somewhere.
DVS mentioned something on here a while back about renting excavators and at first it went down a bit sideways with me then I looked back at our jobs for the last season where we used an excavator and honestly we didn't rent any one machine enough to make a purchase worthwhile---but we used an excavator almost every week. Size is a huge concern with an excavator and it isn't one size fits most. Just make a good arrangement with your local rental place and encourage them to keep a full range of machines in stock and you will always have a well maintained machine of the right size for your job that you don't have to worry about paying for through the winter. Our rental yard has one 17, four 35's, one 45 w/cab, heat, & wrist, two 55's, and one 100. Everything has a thumb and two buckets except the 17-and we are working on them to get a 27 for the rental fleet as this would probably end up being the machine we rent the most.
I would hold my money if I was you...