Sagging springs on lifted jeep - Which replacements?

My jeep is lifted 4.5 inches but is sagging bad in the rear. It's got a lot of miles on it so I don't really wanna drop a bunch of money on brand new 4.5 inch lift springs. What kind of bastard pack can I build or are there any cheap 4.5 inch lift springs out there? Thanks in advance.
It's a '97 on stock axles

S-10 springs under a stock main give about 4.5". How much is your rear sagging? You might not need much to lift it back up. There any real suspension shops near you. They could re-arch your pack. You might just want to slip a leaf into the pack you have, do you still have the stock pack?

I am having the same issue. Not trying to thread jack but, would adding the main leaf from my old stock pack to the lifted pack give it a horrible ride? Better arch? My leaf springs are pretty much flat since I have installed a rear bumper/tire carrier. Thanks.