Fictionwise is running a 100% rebate deal on three authors this weekend: Sue Grafton, Janet Evanovich and Lora Leigh. Every one of their ebooks are included and you can use existing micropay to pay for the titles (except for those on the NYT Bestseller list, which require payment by Credit Card or PayPal to qualify for the rebate: Plum Spooky by Janet Evanovich and U is for Undertow by Sue Grafton).
Note that all of the titles are available only in DRM'd formats, so are not Kindle compatible. Most are available in Secure Mobipocket and eReader (nook compatible and the FW reader app on the iPhone) and quite a few show an ePub (nook/Sony) or PDF option (Sony). All, of course, have free reader software options for the PC and this is a cheap way to build up your library of these three bestselling authors.
If you don't have any credit there, you could start with the two NYT bestsellers above, then use that credit to buy a couple of books at a time, repeating until you have purchased them all. The deals on Evanovich are set to end today (which often means about 10am EST) and the other two end tomorrow.