There are a few specialised electric cars for drifting. they all use 7.2v batteries. Here is a list of them.

Hpi sprint 2 stage D

Yokomo Drift Chassis (RTR)

Tamiya TT-01D

Tyco Drift Kings

You can also get most 4wd road cars to drift if they have slick tires on.
Some nitro cars will drift with treaded tires as they are so powerful there is a lot of wheelspin.

If you have a 4wd nitro car, you can buy an HPI stage D kit for about $200.
but unless you are loaded with money, that isnt usually the best option.
But if you want to drift without having to pay much for a stage D kit, you can fit pvc or abs tires onto any 4wd road car.
Only do this if you are a professional. Only buy second hand drift cars if you can build cars yourself.
If you are new to professional rc, I recommend the tyco rc as it is cheap and easy to use. If you are alredy into pro rc, get the hpi because it comes assebled exept without a servo, reciever and speed controller. You could also get the TT-01 but it comes as a complete kit but is easy to assemble. Or you could get the yokomo rtr. If you have good experience you could try and build the kit.

I hope you have found my advice useful.

Cheers

Alex