It's more a case of finding a second hand set rather than how much you will pay, lamin-x is a good option but it will reduce your light output, i used the smoked and the lite tint before opting for a set of S4 lights.
coz they are cheap!! I guess its weighing up the time and hassle factor coupled with the fact that the majority of them get condensation very easily from what i have heard. no doubting they look pretty good tho..........