A shackle reverse lift will give you a little bit of lift and make cruising down the road a bit softer, but it is a bit of work. What lift you go with really depends on what you are planning on using it for.
If your just looking to clear your existing tires a little bit more, I would pick up some 1.5" lift springs and call it good. They are a simple bolt on procedure and work great for a Daily Driver/Light wheeler. Low Range Off Road has them on their web site, or give Hawk Suzuki a call and they can hook you up.
I love my SPOA, but you should do some searching on the forum for SOA or SPOA in order to see some of the issues and what people think about them. Unless you plan in running 31" or greater tires I wouldn't bother. And if you are planning on some 31" tires, expect to either re-gear your diffs or change the gears in the transfer case.
Personally, I dislike body lifts. Just my preference that you take it out of the body or lift the suspension.
Now as for what is the quickest and the cheapest, it all depends on your fabrication skills. I have done a zero dollar SPOA before. If you want a cheaper SPOA though, I would recommend the Sky Manufacturing kit.
