The cheapest way to get 4 inches in the front... Great question.
Craigslist.
Salvage yard.
Above mentioned "zero rates" give a solid inch for $40.
3 to go!
Look for used gear.
You could buy something LIKE one ton (K30) springs salvage for super cheap and get lift that way, prolly an inch seems reasonable. Somebody around here knows, it just aint me.
Thats prolly 3 inches 2.5? at absolute best, but it suuuuuure would be cheap.
2.5 will clear a 33...
Blocks in the front are bad. I don't know why but dont do it lol.
My other thoughts involve a local spring shop. "Re-arching" is possible there but IMO that is running close to buying new springs money most likely. I dont know that.
New springs aren't expensive really.
Consider adding a "spring pack" or something similar in addition to zero rates and one tons. That's some special few hyper arched springs to stick in the middle of the ones you already have. I think thats what it's called...
You could 1 inch body lift for pretty cheap.
You could prolly get 3+ pretty easy for pretty cheap.
There are other things to consider.
Brake lines
U joints / driveshaft stuff
Shock absorbers
Steering arms
Bolts and hardware
Dont bite off more than you can chew.