Here are some mods under $150 I like. Some I've done, some I haven't got to yet. The roof basket is $250, but cheap at the price.
Interior
Maglite w/ mounting brackets - $40 - Bass Pro shops
Fire extinguisher w/ mount - ???
Rubber floor mats - ???
Inclinometer - $15 - RV store
Midland 75-822 handheld CB - $100 - Walmart
Lighting
Silverstar H13 headlights - $40 - AdvanceAuto
Silverstar 9145 foglights - $40 - AdvanceAuto
Fog light stone guard inserts (size 600H) - $10 -
TeakaToys
GM underhood engine light - $50 -
pfyc.com
Exterior
H3 source sticker - $5 -
SOMO source motors
Short radio antenna - $15 -
Valeo windshield wipers - $45/pair -
Tirerack.com
Mud flaps - ???
BVG All-Road roof basket - $250 -
racknroad.com
Locking fuel door (black) - $90 -
suvxccessory.com
CB antenna firestick - ??? -
firestick.com
Off-road
Staun tire deflators - $50 - ebay
NATO spec no-loss valve caps - $15 -
mesa4x4.com
MasterFlow MF-1050 or 1052 onboard air compressor - $50-60 - costco
Purple Cranium differential guard "spider" - $80 -
purplecranium.com
Tail light guards - $100-150