Best bang-for-the-buck is spacers. For $200, you can have more ground clearance & fit bigger tires. Because the body lifts don't provide ground clearance, IMHO they're a waste of money on anything other than a mall crawler.
Body lift: cheap, but doesn't actually give more ground clearance
Spacers: cheap, moves the frame / diffs / gas tank etc up giving more ground clearance, but suspension travel (and therefore articulation) remains the same.
Bigger springs & longer struts / shocks: Right now, OME is really the only option. It's the most expensive ($700.00 - still cheap for what it is), but it's a "true" lift - giving better ground clearance, vastly improves ride quality, and adds articulation.