Samurai

Guys, I'm very fresh for this forum as well as using cars. I'm planning to buy an AE 81 GL (16-***) car. I've never used a petrol vehicle & know nothing about them. I wanna know the prices, availability of spare parts and especially the fuel consumption of this kind of cars. The car that I'm planning is a 4 forward 1.5L one (With power steering). Are the 4 forward cars consuming fuel more than 5 forward? And what is the life time of this sort of engines (How many kilo meters)?