if ur looking cheap mods you can always rustaline the interior and take out the carpets.. uhmm.. some extra lightting isnt TOO bad in price.. but IMO.. to make a wrangler your own, is a lot in the lift and the tire/wheel combo. I got the 4in rc lift for around 500, and some 33x10.5 BFG KM2s for about 1000 after mounting, balancing, and install and what not. and my jeep looks completely different. those two things were the biggest things to do for my jeep.
Another cheep mod I've seen lately is the dash lights. You can order LED bulbs in pretty much any color that will plug into where your out dated bulbs are now. If I remember correctly there are 7 bulbs ( tach/speedo, 4 gauges in the middle and the heater/ac control) that you can get to get to by just taking some screws out. pretty much a new looking gauge set for less than $30!
Customization can goes as far as your imagination and wallet or wife will let you...lol
Alot also depends on your skills and abilities....scrounge and fab your own things for the best price. Lets the jeep take on your personality and originality!