Rayon thread has a lovely sheen, but is not as colorfast as Polyester. If you are doing decorative items, rayon may be a good choice, but for items that will be laundered a lot, especially kids clothes, poly is probably your best option. Many machines are fussy as to the brand of thread, so you might want to get a single spool of a particular brand before you buy several. I have a Viking that will take anything, but the Brother I had before would not sew with Threadart, however, your machine might love it! I also like Isacord and Madeira poly.
I get my thread & stabilizer from all stitch. Their Madeira is $2.63
http://www.allstitch.net/department/...mber-10075.cfm
I would also take the time to read the informative articles on general embroidery and stabilizer selection on their education page:
http://www.allstitch.net/department/....cfm?killnav=1