It really depends on how much you want to spend & how you want it to look when you are done. I used to do body & paint work at a collision shop & have painted cars outside(at home) before that came out fine with some color sanding & buffing. You can also make a terrible mess doing it that way and can get in trouble with the EPA.(I didn't have to worry about that 25 yrs ago)
The paints of today are a lot better AND a lot more dangerous. You can use enamel which is cheaper but won't last as long. I just bought 1 & 1/2 gallons of original color urethane (Sikkins)with the reducer & hardner for my truck for $160.00. I am going to have a guy I know at a body shop paint it for me. I don't have the proper equipment at home AND without the proper resporator the isocianates(?) in it can kill you.
Check with a couple local body shops & ask where they buy their paint from. Go to the local paint dealer & ask them what you need for supplies & safety equipment. If you ask a body shop how much to paint your truck they probably are going to start around $3000 & up. You get what you pay for. If you have a SAFE place to paint it, maybe a booth someone lets you use, would try it myself.