There are some really pretty ones here... http://www.birchplaceshop.com/collars
Glad I can help. That shop has almost anything to suit your sissy needs. I'm looking to order the "Sissy Maid" necklace and a pretty frilly sissy maid dress from there soon.
If you're on a tight budget, do you really need a collar? If the dynamic is there, who cares about a physical representation?
you do need a wedding ring. it's a symbol of comittment.