I probably have a warped view from living and shopping for 4Runners in the west, but in my experience if you want one in good condition with low miles like that you're going to pay unless you get really lucky. Assuming everything is good on the Runner the price is not really out of line and the seller will be able to get it. It's right at NADA retail so not priced above what your insurance will cover, you could get a loan on it, etc. If it were on the west coast they could probably get more- it's only higher miles that goes for anywhere near as low as KBB or Edmunds.
BTW, it does not have a locker- that was not an option after 2000. It's got a multi-mode transfer case, which gives you 2WD, AWD (can drive on pavement), or full 4WD. There are a couple of iffy things like that in the ad, so I'd check it out thoroughly. Might just be that the seller doesn't know what he's talking about, but my scam meter came up slightly when I read it. On the other hand, if it's legit it's a nice truck and will probably sell fairly quickly.