I have heard that a lot of the machines that they sell at craft stores for polymer clay are cheaply made and break easily. I will admit that I do own one of those same machines but I use it for travel. (Like to guild meetings and the like). I bought it on sale and use my employee discount as well. (I work at a local A.C.Moore).
I have an Atlas that my husband bought me years ago. I have never had any problems with it.
My husband got it a specialty food store. I have also seen them at the higher end cooking stores, like William and Sonoma. I rarely have seen them at thrift stores but every now and then I find them there. I also know that you can find them at garage sales.
Another place to look is on e-bay. Although you have to becareful with shipping costs. You can get lucky though.