This weekend, August 11-12, 2007, is a sales tax holiday in Massachusetts. According to Dept. of Revenue TIR 07-12 , "on those days, non-business sales at retail of single items of tangible personal property costing $2,500 or less are exempt from sales and use taxes, subject to certain exclusions." The TIR provides more specifics on what is excluded, including motor vehicles, boats, meals and more.
While the benefit is more psychological than financial (even a 5% off sale on another day results in a lower overall cost to the consumer), the holiday does boost sales of retailers considerably. “'Sales this weekend will be comparable to the weekend before Christmas (approximately $500 million is taxed & non-taxed retail sector sales), at a time that otherwise stores would be dead,' said President of Retailers Association of Massachusetts Jon B. Hurst," in the Westborough News.
For more information on tax issues, see Mass. Law About Taxation.