This is a really old post but since I haven't seen the subject talked about much I figured I'd update it. You can buy washer parts and the bellows individually from this corvette parts supplier for $16. It's under "miscellaneous".
http://www.grilleteeth.com/shop/shop.asp

 

Thanks! And here I thought I had seen them on the Help Aisle counter...

 

You did
It's Dorman/HELP parts #54000 or 54001 - can't remember exact number but I bought one @ 6 months ago in Texas parts store to fix one of my brothers farm trucks washer.
Think it cost a woppin' $6 IIRC ...