Propane (for cooking and heating). Groceries, of course. Repair/maintenance on the RV. (With your budget you will likely get an older RV, many of which will need some work.)
Insurance.
A way to get around. The motorhome is transportation, yes, but also your home. With a motorhome, every time you need to leave the campsite for something, you have to undo all the hookups, unlevel the camper (assuming you had to level it), and make sure your site will be available when you get back. Then level/hook it up all over again when you return. And motorhomes suck gas like you wouldn't believe. A class C big enough to live in will probably get about 9 mpg.