Fiskers 45mm blades
 

Walmart has a pack of 5 blades for $16 on sale today. Good deal

Connecting Threads are 5pk. @11.99

I just bought some from JoAnns for 60% off and I had a 25% coupon to add to it...Cheap...

I send my old used blades and get these Olfa blades in return: from L.P. Sharp.com

Get brand new blades in exchange for your old ones
5 (five) blade minimum order
OLFA Blades
28mm - (1" size) - $2.30 for each blade exchanged
45mm - (1 3/4") - $3.50 for each blade exchanged
60mm - (2 1/4") - $5.80 for each blade exchanged
Generic Blades
28mm - (1" size) - $1.90 for each blade exchanged
45mm - (1 3/4") - $2.20 for each blade exchanged
60mm - (2 1/4") - $4.70 for each blade exchanged

FREE SHIPPING in the United States!

I bought several packs of five from Connecting Threads during the sale. I like the way Clover packages the blades, very classy.