The cheapest would be the suspension special from NTW. So cheap they can't tell you its brand name Superlift stuff. They are old school ride but very good quality. I have that kit in my '72 due to budget concerns (
). The best for the money is Tuff Country, IMO. That is my prefered brand I have used on quite a few trucks.
One thing to consider with better riding springs is the reason they ride better...flex. And flex is what draws the line between rub and clear on a marginal clearance lift.So does wheel width. A flexy suspension with allow more compression over the same angles putting the tire up into the body more. On my '72 K/20 with 6" EZ-rides, 315/75-16s mounted on 10" wheels could rub a bit at times. Very avoidable, but I am sure stiffer springs or 8" wheels would have eliminated that issue. I had to extend the rear shaft 2" for proper travel. Nothing necessary beyond that. They give you a transfer case drop but that's on the shelf. Totally not needed. I personally feel those only serve to make the front angle steeper when the longer rear shaft is not the issue. It puts a steeper angle on the front shaft by cocking the engine-transfer case unit down in the back end. Dropping the engine mounts the same amount is the only way that deal makes sense to me.