First, you should do some research on what equipment you like to purchase. If you go to the discussion board at
http://www.umpire.org, there is a whole section devoted to equipment. Umpires are glad to share their experiences about equipment and suppliers.
As for the supplier, you can not go wrong with the name guys - Honigs or Gerry Davis. If you buying a particular item (i.e. West Vest), it is likely you find a better deal at some lesser known suppliers.
Finally, as a satisified owner of the Gerry Davis plate shoe, simple nail polish removed the logo.