The OSA optics kit is now sold by Edmund Scientific:

  Optics Discovery Kit, OSA Optical Soc. Am.
  http://www.edmundoptics.com/products/displayproduct.cfm?productID=1865


FOR INEXPENSIVE LENSES, TRY:

   AMERICAN SCIENCE AND SURPLUS   (request their mail-order catalog!)
   http://www.sciplus.com


They sell:
  http://www.sciplus.com/category.cfm/subsection/21/category/188
  http://www.sciplus.com/category.cfm/subsection/category.cfm/subsection/21


ALSO TRY:

  SURPLUS SHED OPTICS
  http://www.shareasale.com/r.cfm?b=98307&u=371722&m=14450&urllink=&afftrack=

  EDMUND SCIENTIFIC
  http://www.scientificsonline.com/optics.html?limit=40