If you want to try building your own strop, here are some sources for parts:
Small amount of leather:
Tandy Leather Factory - Natural Cowhide Leather Strips
Backings:
Poly webbing: Special Polypropylene Webbing 3 inch - from www.ahh.biz
3" Cotton: Tambour Roll Door Tape or Webbing - Kennedy Hardware LLC
Heavy 2" cotton: Heavyweight 2" natural twill tape
3" Heavy Poly: http://www.strapworks.com/Heavyweigh...ene_p/hwp3.htm
Hardware:
misc. hardware: USA Lanyards Wholesale Store - ID Name Badge Holder Lanyard Supplies - usalanyards.com
D's and misc: Metal D-Rings
Cheap D's: Tandy Leather Factory - Solid Dee 2" (5.1 cm) Nickel Plated 10/pk
Large D: Tandy Leather Factory - Rigging Dee Flat Cast 3-1/2" Stainless Steel
Cheap Chicago screws (a little long for most strops): Saddles Tack Horse Supplies - ChickSaddlery.com Chicago Screws - Pack Of 10
Chicago screws: Tandy Leather Factory - Chicago Screws
Tools:
In addition to an exacto knife and a straight edge, you may want to look into a 2mm edge beveler and a slicker.