I recommend a sewing machine by Simplicity/Baby Lock/White. They are all the same machine and manufacturer just different brand names.
Make sure it's easy to thread, and that it has snap on presser feet, not the screw on type. I got my last two machines from QVC, I found that they are at least 20% cheaper than in the stores. QVC just had a sewing day so they only have two Singer models left but they should be restocked soon. HSN has a Simplicity simular to mine for $150. Also make sure that they will sew through denim.
Oh, another thing, get one that has a rounded machine body, not square with sharp corners. The rounded design keeps the fabric from getting caught.
Thanks everyone, these are great tips! My first project is going to be cat beds. My girls love to lay on the satin lining of my winter coat and on my terry cloth/chenille bathrobe, so I am going to make one side satin and the other side terry cloth. I have had cats long enough to know that they probably will take one look at their new beds and head for my bath robe, but at least I will have made something!