Yep. Home Depot and Lowes have them, often near the tool crib, sometimes in the paint aisle.

Ace & True Value stores sell them too.

Remember: Never, ever ever put the kitchen extinguisher over/near the stove, that's the last place you'll want to reach if there's a fire there! Don't put it under the sink, you won't be able to get to it.
Mount it to the wall, in plain sight, away from the stove. If you have a spousal approval issue, look at these models that come in white:

http://www.lowes.com/lowes/lkn?action=pr...&lpage=none

or this one (you can get at Home Depot)
http://www.homehero.net/fireExtinguisher.html