You can do it two ways;
either you can keep your stock toyota 5 spd manual box and get a adapter between the engine and transmission or you can use a chevy th350 or 400 automatic and only use the toyota transfer case. That kit is a bit cheaper.
Any chevy small block from 262 to 400 cui will fit, most of my friends use the 305 which is an excellent engine (even that will burn the clutch if you aren´t carefull). A big block will also physically mount but is a bit tighter to squeeze in, especially if you want the radiator mounted in the front (some mount it on the bed, behind the cabin if you´re looking for a real potent offroader)
You will also need special engine mounts and a special oil pan if you don´t have the truck lifted, the front axle need some more clearence with a v8.
As said befor a special starter motor with a smaller nose cone is recommended because the adapter is cast with a smaller hole, or you can just take an angle grinder and make room for the stock chevy starter
You also need a flywheel for the clutch and either a special kit including a gm 10,5" clutch disc and pressure plate or the toyota OEM with mods on the flywheel (the pressure plate must be fitted and balanced on the flywheel and new holes must be drilled)
I´m not sure about the pricing since the shipping was a big part of our expenses, but you should manage to getaway below $1000 depending on which parts you´re choosing.
I don´t bulid the trucks myself, it´s actually some friends down in Tenerife (an island of the african west coast) I just import the parts since they don´t know any english. If you want any pictures, I´ve got a ton of them!
Good luck/ Andreas, Sweden