Women's Health magazine holds a giveaway a day, every single day. Once you register with them, all you have to do to be entered in the drawing is vote in a poll. Each day you vote in the poll, you'll be entered to win that day's prize - the winner of which is announced the following day at noon. Don't forget to enter for the grand prize every month, too. November's grand prize is an HP laptop!
The SITS girls will be hosting "Merry SITSmas" on December 8th this year. It's a one day giveaway carnival - hundreds of bloggers will link up with giveaways they are hosting, plus SITS will be giving away prizes through-out the day. (During a similar event held by SITS, I won several items - all in a day).
I enjoy a few sights that specifically review products and/or showcase special deals regularly. Fantabulously Frugal & Mudpies and Maryjanes hold frequent giveaways. A Cheap Chick, Luv A Bargain, & Slickdeals.net offer special savings announcements and coupon codes. They do all the research, so all you have to do is take notes!
Some bloggers also host giveaways on a regular basis, such as The Apron Goddesses, who give away an apron a week.
These are just a few of the sights I have found that help me save money and/or host a lot of great giveaways. If you have any you'd like to share, please leave a name or link in the comment section.