People frequently mention stacking deals, and I've recently received some questions about it...so, here is an explanation/example.

Stacking a deal simply means applying as many discount, rebates, or other incentives as possible to get the best deal.

A current example.

Drugstore.com is having a clearance sale (up to 60% off), a beauty sale (up to 40% off), and other offers.

It's GNC week, so 20% off of all GNC orders if you have a gold card (which are also on sale).

DH's favorite GNC protein drink/meal, is regularly $40. It's on sale for $27 (savings of 30%). Add on the Gold Card discount, and it's down to $22 (44% savings). There is free standard shipping on orders of $29 (new customers or New Gold Card), or $89 (existing customers).

Free gift with purchase ($8 value).
Free protein drink with purchase ($4)

Go through eBates, get 5% cash back on purchase.

sign in to drugstore.com account, give 5% back on future purchase.

Use a credit card that give 5% cash back on drugstore purchases.

So, what was $160 + S&H ($175) is now
$73 plus two free gifts (or $61).