Por 15 was my first suggestion, but a 17 yr old with little disposable income, hmm. How about either flat rustoleum or 1 gal of herculiner. Look at their website for rebates. Dont buy the kit, just the gallon then use a chip brush & gloves and you've at least 2 week ends of projects between bumpers, undercarriage & floor.
'90YJ Hard & Soft w/Full Drs; 4.2 Rebuild w/ Webber, 30x10.5; Interstate MegatronII D34; Mods: Rock Guards; Hi Lift Inst; Herc'd Tub, Front & Under; Elev Rear Seat; Scty CntrConsole/ Overhead&Rear Boxes; KC Lights-Fr & Rear; PA Sys; Gauges; Int Lts; Batt/Alt Cable; Heater Mods; 8K Winch, KargoMaster Rack w/Yak Megawarrior Basket; Ground Lights (4);Dumped - Optima Yellow after only 4yrs