The standard Dexter sounds like the one you want. they are available at craft and hobby as well as on line.

They range from the Dexter and Altos to the C&H type all the way up to the wall mounted Speed Mat Cutter from Esterly.

You might also consider the Logan Adapt-a-rule.

http://www.logangraphic.com/products/straightedges/

Thanks for the input I bought a cutter today, and now I have another question. Where is a good place to get matte board? The store where I bought the cutter wanted $14 a board. Is that a good price?

Not knowing where you live, it's difficult to recommend a local supplier. I answered someone else looking for materials and referenced a resource web site that lists suppliers who sells wholesale to people doing art shows. But the short answer is to purchase mat board from United Manufacturers. They're the largest mail order framing supply business in the country.