Flash media at the moment is alot more expensive than Hard drives.
Well since black friday is this friday, you will be able to get some kick ass deals on Hard drives.
80 gig SATA or IDE HD will prolly put you back $20 on black friday.
Also watch for deals in the newspaper and\or online at fry's cas they have some really bad ass deals from time to time also.
The way that I usually buy Hard drives is online at either
www.newegg.com or
www.tigerdirct.com
Depending on how old your computer is you might not have SATA...
Hope this helps...