Buyer behavior is a fascinating thing to watch, particularly as we face rising gas prices. The latest trend is for businesses to offer free gas as an incentive to purchase a product or service. Even a blood bank has taken the step, according to this Business Week story:

Summer promotions are nothing new to the Northern Ohio Blood Services Region of the American Red Cross. Blood donations can drop 20 percent in summer months as high school and college students scatter, so this year the group is offering summer donors the chance to win a gas card. The prizes are one $3,000 gas card and five $500 cards.

After the blood center’s promotion launched this week, donations rose 6 percent over the same period last year — although the number of days available for comparison is small and it’s not certain the increase is due only to the raffle. But organizers say the early numbers are encouraging.