In a press release, the Mets stated:
Fans donating blood will receive a voucher redeemable for one pair of tickets to a select Mets game in April 2012. In addition, fans can show their voucher at the Mets Team Store at Citi Field to receive 15% off regularly priced merchandise. Season Ticket Holders who give blood can show their ID card to get 20% off regularly priced items. The discount will only be honored Thursday, January 5.If doing a good thing, such as potentially helping save someone's life by giving blood, isn't enough to get you out, Mr. Met will also be on hand for pictures. You'll have to be there by noon for that perk, however.