I usually use a Nikon L12 for bead photos. Set to Museum/Macro, rechargable batteries (goos ones) work better than disposable batteries. Light tent, flash off. Set exposure to +0.3 or +0.7 makes color correction almost unnecessary. I crop in photoshop.
The camera was ~120 at Sams last summer.
Pro's - cheap, good macro, works well with rechargable batteries, SD memory
Con's - since it's really not that adjustable, depth of field for jewelry shots is so/so, focus gets poor as batteries get weak, so keep a set charging.
Here are a couple examples.
Now, these aren't as good as you'll get with a camera that allows for more adjustments and a real macro lens, but it's quick, and inexpensive.