best way i've found
say you want a hard drive...
1) see if staples carries it...how much is it & can they deliver it in 1 day...
2) find the best price you can at another store (bestbuy, circuit city, etc) or online...but for online orders you have to include their overnight shipping charges if staples offers 1 day delivery...if staples offers 3-4 day delivery just add their regular shipping charges
3) place the order online at staples.com, using the dashbar (dash.com 4% off) and use a coupon from the usual sites (techbargains, fatwallet, etc.)
4) wait a little while after you place your order...then call 800-3STAPLES and tell them you would like to do a price adjustment with _______________ (wherever you found it cheaper)...they will put you on hold, verify the price/shipping/instock & you should get a refund of the difference in price