Sign up for Pretzelmaker Rewards to receive $3 off any Pretzelmaker purchase for your birthday. The email notification that the $3 off coupon is in your Pretzelmaker app is sent 1 week before your birthday and it is valid for 1 month, which extends your birthday timeframe a bit, if you are trying to schedule and stretch out your birthday freebies.
To join the Pretzelmaker Rewards program, go here and click "Sign Up." The page also has details on how Rewards members earn more points, such as referring friends and earning points for spending money at Pretzelmaker.