About how much would it cost to have a quality lift put on my 2008 F-150 truck?

depends on how much lift you want.like this one: .http://suspensionconnection.com/cgi-bin/suscon/22905.html $200-300 (shops charge $40-70/hour less than 2 hr job) for this one.
one like this:http://cardomain.com/ride/2988593 expected to spend $1000-1500 for parts plus labor 6+hrs http://fourwheeler.com/techarticles/suspension/129_0901_2004_2008_ford_f150_rough_country_lift_kit/index.html

How much lift r we talking about here? What size tires r u going to put on it?

You can do anything from a leveling kit to just bring the front up even with the back, to a ridiculously big lift that cost tens of thousands of dollars by the time u r done.

The f150 l have right now, l did a torsoin bar crank up front (free) & an add a leaf in the back ($100) & a 3 inch body lift ($175) so for $275 l lifted the truck 5 inches.

Then the real money is spent on tires, rims, & regearing after that.