It's pretty easy to do yourself. In my case I had to have a shop compress my coil springs and put the ToyTec Spacers in, b/c that's really dangerous to do yourself if you don't have a proper coil spring compressor. That cost me $90, but other than that the install is not that difficult, and only cost me a few hours of my time.
On a 1-to-10 scale (1 being an oil change, 10 being a SAC), a ToyTec install would be about a 2 1/2.
If you take it to a shop like ORW, or somewhere like that, they're going to charge you anywhere from $750 - $1000. If you're uncomfortable doing it yourself, take some of these guys up on their offers, and buy some beer. I would NEVER pay a shop to install a lift kit.
For whatever it's worth, I could have done it myself, but not in 3 hours, so I chose to pay someone to install my Toytec/OME lift. With the family and other crap to do around the house I couldn't blow a whole day, which is what it would have take me....
I had mine done a big o tires in HB and IIRC, they charged me $300.
I've done it twice now and I can tell you from experience, 3hrs is way to long. The 2nd time it only took twenty minutes to get the struts out, about 30 minutes to compress the coils and switch out the shocks and then it took about twenty minutes to put it all back together. That was with a couple of coke breaks and helping someone change their shocks on a runner. It really is an easy process and I am not a mechanic by any stretch.
you should probably state where your at. If in socal, there are tons of us that could help you.. if not.. maybe your local chapter. BEER & FOOD are the best way to get stuff done.. All mechanics have this weekness...lol. Also depends on if your lifting the front and rear or just the front... rear leafs take a little time.. but not bad.. shackles are easy and fast.. the fronts are easy if you coil assemblies are already built.. if not take them to a shop to be assembled as coil spring compressors are not that safe. If you dont have a super rusted truck everything goes by very quickly. IMO its not worth it to take it to a place and pay to have it done.