For super budget and reliability...
35" tires, 2-3" lift, welded rear third member (cheapest of cheap locker system), sliders, t-case skid, bumpers...
Cheap options for suspension setups include but are not limited to, moving the rear springs to the front, 63" Chevy springs in the rear, TrailGear springs (You'll replace those in a year though). You can obtain a 2" lift with simply a 2" longer shackle. Stay away from blocks or add-a-leaf systems, as those will work against you.
If I were on the strapped budget, i'd do welded diffs, spring over the front axle, shackles in the rear to level out truck, 35" tires, hack the fenders, HiSteer, sliders, tcase protection.
^ That's a budget wheeler that you can have fun with and still be well within the reliable spectrum... Once you go to 37"s you want to seriously look at chromoly axles, Long fields and so on.. Also, you would want power steering, which is something you might want to do when you upgraded to HiSteer during phase I anyways. 37"s also bring on the need for lower gearing, 4.88's, or my favorite 5.29's. T-case gears are not essential, but certainly allow you to have more control over power and torque at the tires. Don't get caught up thinking that dual cases is the sh!t either. You can do plenty with a single case with lowered gears. Once you start to get more comfortable in your ability to wheel the rig, you will constantly be pushing yourself.. Think seriously about building a good internal rollcage as early as possible in the evolution of the rig. Safety should always be first and foremost.
There are loads of options with any build.. Hopefully some of my list helps you out with a truly 'budget' build.
-Jason