Hehe, define "budget." That has different meanings for everyone. There's cosmetics, like derped grills, blackout badges, sticker hp gains, interior leds/skins, etc. Then you can get into some of the little bit more spendy mods, like fog like replacement kits, seat covers, turn signal/headlight blackouts.
Depends what you're looking for out of your truck and what you want it to do/want to do with it.
Good luck!