Its the same as buying anything, if you are not hands-on with something that you want, then anyone selling could take you for a ride.
Its good that you have been following the forum here; suggest you keep on following it and once you are sure what you want and are aware of ALL the nitty gritty stuff involved in it, only then approach a dealer.
The FJ40 is a good choice to start with, but if you have little knowledge on what you want, then you might get palmed off.
Remember that most of the FJs are recent (last 2 year) military auctions. 1st thing you need to see is when it was auctioned and when was it registered (advisable to go for a registered one)
Most people who picked up complete lots had them made, put in diesel engines, buffed up the paint job and put them up for sale. Those are a definate NO NO for a 1st timer, as you'll be spending most of the early 6 months of ownsership getting things fixed.
Suggest you go for some that has been used by an individual as a personal vehicle and is selling to upgrade etc etc. You might have to pay a premium on such vehicles, but they would cost you cheaper in the long run, unless you want to replace major components like the engine or transmission.
I'm afraid, there's no standard price list for these vehicles, as each one is unique in its own term and shows it too. So start off with a budget & keep an extra 50k cushion in that.