I've been coveting this for a while now.
http://www.harborfreight.com/4-inch-x-36-inch-belt-6-inch-disc-sander-97181.html
be sure to search online for the 20% discount code.
I apologize... I didn't realize you were talking about cutting pieces out. I thought you were speaking of carving. I would use a metal straight edge, stand as Dwight says, and make sure I cut deep and smoothly. As for corners and jagged edges... That tells me your blade isn't sharp enough. When I get that kind of stuff, I use a pair of razor sharp dress shears and snip those ragged bits away before I sand. (and go sharpen the knife)
The scissors I have are Fiskars Razor Edged dress shears. I've had them for years so I don't know how much it will cost to get a pair.
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