Couponing

It's long been a big business but, according to the National Retail Federation BIGblog, coupons are once again "hot." Mobile apps, billion-dollar babies like Groupon and even the TV show "Extreme Couponing" have made it so.

Coupons primarily influence trial and forward-buying. They are a great tactical tool. And, according to the NRF, they do impact sales.

But not like the point-of-purchase where two-out-of-three purchase decisions are made. If you want to make a lasting impact on purchase decisions, invest where most purchase decisions are made: in-store.