Free: Contests & Raffles.
Heavy shot is far from the best. There is a lot of good ammo out there. I buy what is on sale:http://www.rogerssportinggoods.com/ammunition-federal-steel-c-35_36.html
I have tested the blindside shells with horrible luck myself. I thought they were the coolest thing till I shot them. Worst patterns I've got form any load out of five different shotguns with several chokes in each.