Hello Shyrell,
I have ordered diopters from B&H Photo:
http://www.bhphotovideo.com/bnh/controller/home?ci=1&sb=ps&pn=1&sq=desc&InitialSearch=yes&O=SearchBar&A=search&Q=*&shs=diopters
Also, you might look at KEH Photo:
http://www.keh.com/hmpg/index.cfm
I've done business over the years with both entities and have always been treated very well by both, and I've been very pleased with their services.
Take Care,
Marilyn
