Sometimes Office Supply stores (Office Depot, etc) will sell you one in their copy department. I don't know how much they are, but if you just want one to try out, it might be a good way to do it.
I found some of the ones you can put thru an ink jet printer at Big Lots. They were $1.99 for 10. I like them for printing titles or sentiments and then using as an overlay on cards. Never made an ornament. (Yet!)
HTH,