Formal:
* Stingy
* Parsimonious
* Frugal (can be a neutral term, but often implies excessive frugality)
* Penurious
* Niggardly
Informal:
* Cheapskate
* Scrooge
* Tightwad
* Penny-pincher
* Miser (this one is very direct)
Figurative:
* A skinflint
* A penny-wise and pound-foolish person
The best term to use depends on the context and the tone you want to convey.