Tune-up?

I bought an used car just a few weeks ago at 82k miles, 83k now.

I wanted to do a tune-up, what would a good tune-up be defined as? What things need to be changed? And also, around what price? Also, is there any performance gain with this?

Car: 01' Firebird V6 3.8L

Thanks

There shouldn't be any performance gains.
Although you may pick up 'lost' HP for old plugs and old fluid if the old parts are really worn down.

Change fluids, plugs, check wires.
Coolant, oil, tranny fluid, etc