I don't know the deal with Astra blades lately, but several vendors on Amazon are offering 100 blade packs for less than $10 shipped.
http://www.amazon.com/Superior-Prem...AAEAL4S4CJG99&qid=1341016350&s=generic&sr=1-4
http://www.amazon.com/Superior-Prem...AAEAL4S4CJG99&qid=1341016350&s=generic&sr=1-4