RITZY! I can't believe you paid that! I buy my blades 10 at a time from
http://www.hancocks-paducah.com/ for $40! Look for specials and free shipping offers! They usually go on sale in January for $30, but who knows in this economy.
And here is another useful site:
http://quiltshops.com/ Search for anything you want. I usually set up a spreadsheet that includes shipping cost and sales tax to see where I get the best deal.
You can search for them and see if anything is on sale, but Hancocks is usually the cheapest. A little bit of high math here: If you buy one blade at a time ten times, you spend $100. If you buy 10 at a time for $40, that leaves $60 you can spend on more fabric! (Hopefully on sale, but some of them never reach the sale stage.)