I'm not sure what kind of a deal you guys are getting on these, but if you search around on ebay you can get 50 of them for around 8 bucks, including shipping.
Great blades.
EDIT: I just saw westcoastshaving.com has them for even cheaper. 100 for 12 bucks.
These are both the famous Israeli Blues. They're popular and inexpensive. Buy 'em online for the best prices.
I'm partial to the U.S. Personnas sold generically all over the States. Israeli Blues are their equivalent to me. Very comfortable in any ax I choose and they've always been good for at least five good shaves.
Ya can't go wrong! And if you do, there are dozens of people here who'll be happy to work a deal with you for your remainders.
... and it shaves as comfortable on 9 as it does on 5.
Now there's a satisfied customer! And a versatile blade. Scoop 'em up while they're still cheap! I suggest 1000 or so ...
Lets see 1000 blades, changing every 4 days..........That is 4000 days, hell thats just shy of 11 years worth. I better get more.