If you have been looking for mapping software then this is a perfect deal for you. Best Buy is currently having a sale on Microsoft Streets and Trips 2006 for $19.99, and there is a $10 mail-in rebate when you order it which makes the price $9.99! The normal price for this edition is $39.99 so 75% off the original price is a pretty HOT deal!
Before you jump in and order it you may want to make sure that this software is right for you. Delorme currently has a very powerful alternative called Street Atlas USA. I currently use their product because I have had bad experiences in the past with Street and Trips (mostly GPS navigation problems). I know that Microsoft Streets and Trips 2006 is supposed to have many updates to improve the GPS navigation capabilities. Here is a review by PC Magazine on Streets and Trips 2006. PC Magazine also has a review on Street Atlas.
Hope it helps!