Before you go running to the mall to take advantage of the sales tax holiday in Massachusetts on August 16th and 17th, consumer experts advise that you do your homework to evaluate the sales being advertised and understand the nuances of the law.

"Just because you can save 6.25 percent on a purchase, doesn't mean that this is the best time to buy that big ticket item," explained Edgar Dworsky, founder of ConsumerWorld.org. "You have to compare prices to be sure you are getting a good sale price to start with, and then saving the sales tax on top of that is an added bonus."

Here are 10 tips explaining the rules of the sales tax holiday, and how to maximize your savings:

1. DON'T LET A 6.25% SAVINGS CLOUD YOUR JUDGMENT: If your favorite store advertised a sale on everything but was only offering a 6.25% discount, few people would line up pounding on store doors. But, when the state offers that same savings, shoppers go crazy. Don't lose perspective. Buying things now just to save 6.25% doesn't make sense or save a whole lot of dollars. Prior to the holiday, a number of stores were offering a better deal -- double and triple tax savings.

2. COMPARE, COMPARE, COMPARE: Don't pay full price for an item or settle for one that is being offered at only a lukewarm sale price. Use a shopping robot like PriceGrabber.com to see the range of prices any particular item is currently selling for. Use PriceHistories.com (a service of Consumer World) to see the range of prices the item has sold for during the past year. That way you can determine whether an item is being offered at a so-so sale price or a sensational one.

3. KNOW THE LIMIT: Only individual items of personal property that cost $2,500 or less are covered. Individual items that cost more than $2,500 will have the full sales tax assessed. You do not get the first $2,500 of their cost sales-tax-free.

4. MULTIPLE ITEMS ON ONE RECEIPT: The total on your sales receipt can exceed $2,500, as long as each individual item is $2,500 or less. Any items over the limit will be subject to full tax. For example, at a furniture store, you buy a $1,000 coffee table, a $2,000 dining table and chair set, and a $3,000 sofa. Despite the total being over $2,500, the tables and chairs will be tax-free, but the $3,000 sofa will be fully taxed.

5. PACKAGE PRICING IS PROBLEMATIC: If a store is selling, for example, an HDTV, a soundbar, and a home theater seating package at a single package price, it must total $2,500 or less to qualify. If each piece is also normally sold separately and is below the limit, buying them individually will save the sales tax, but you could lose out on the package discount.

6. COUPONS: To help maximize your savings on things you will be buying, look for dollars-off or percentage-off coupons that can be applied to purchases, even on those items already on sale. And, under the law, those coupons get deducted from the sale price, potentially bringing a more expensive sale item under the $2,500 limit. For example, if a diamond bracelet is on sale for $2,999, but there is a 20% off coupon that can be applied to its purchase, that will reduce the price to $2399, and there will be no sales tax.

7. REBATES: Unless the rebate is an instant one, it is not factored into determining whether the purchase price is above or below $2,500. So, a $3,000 product with a $500 mail-in rebate will not make the purchase tax-free.

8. KNOW THE EXCLUSIONS: Business purchases, cars, motorboats, services, including cell service, utilities, meals, and tobacco are all excluded.

9. DON'T FORGET THE NET: Since many items are cheaper online, don't forget to check prices at Internet stores to save money on both the item and on the sales tax. The sales tax holiday applies to online sales, if tax would normally be charged, even if the seller is out of state.

10. OUT OF STOCK/SPECIAL ORDERS: As long as you order your goods and pay for them in full during the sales tax holiday weekend, even if delivery isn't expected for months, you will still get the benefit of the sales tax savings.

And, if the item you really want is not on sale this weekend, Dworsky reminds us that Black Friday is only three months away.

August 13, 2014