This year was the cheap year. Spent about $250 for oil, filters, RV antifreeze, chassis lube, Eternabond for a small roof tear (got lots of it left for next time). That includes service for the generator. Next year starts out expensive as is time for coolant flush, trans fluid, brake fluid change, brake inspection. Will have oil change and chassis lube done by repair shop that will be doing the rest instead of DIYing it. Will DIY the genny though. Expect about $400 for all the initial work. will be taking a couple long trips so expect that will need to do a DIY oil and filter change. Needs new wiper blades sometime soon so maybe another $200.
I carry the 300 piece tool kit from Harbor Freight. Was on sale for about $160 if I recall. Has pretty much anything you need except channel lock pliers, no clue why they were excluded. Get yourself a decent electrical repair kit. Tape, crimpers, connectors, splices, etc. and a decent multimeter.