Okay, finally a thread I have some idea what to say in.
If you want to tint your own windows, you can, and cheap. I recently tinted my own windows with the tint I bought from SnapTint.com. It comes precut to your specific vehicle's specifications so no cutting, that's the hard part with DIY. I got my tint for $120 or so and that's MUCH better than what I was quoted ($235). Everything arrived in perfect condition (From California to Ohio it took 2 days on basic ground shipping) and included all the tools needed. HOWEVER, just to be sure, get someone who knows what they're doing before you start. Be sure to clean the windows VERY good with baby bath wash and take your TIME, you can't redo this once it's dried so be careful.
Basically how it works is you put water under the tint and put it in place. Then you take a squegee type thing and squeeze the water out and it just dries and the adhesvie sticks. My tint looks awesome if I do say so myself. In Florida, your side and rear windows can't be below 15% and your front windows can't be below 23%. In my opinion, get 35% or maybe even 15% if you have a nice car. DO NOT go with two different %'s, keep it uniform. They very, very rarely pull you over for dark windows, they can add it to a ticket, though, but I'd take my chances.