Yeah I just bought a pair of Wrangler AT's from Wal-mart. Does help a lot compared to the toyo's I had on there. I've always wanted a locker since I was in highschool and learned about them. 1 wheel burnouts SUCK!! Now it's for more practical reasons, that and I pay for my own tires these days lol.
Price wise though seems to me putting an open diff from a junkyard would be the cheapest. Prob Followed by a new carrier like a trutrac or a locker, it's prob more expensive to pout a new rearend under there huh? Though I've always wondered if I could find something with disc brakes how hard it'd be to put that in instead. I'd have to change the master cylinder too though huh. Plenty of options. They all just depend on the wallet.