I have to say, I'm not entirely sure why Tanga is so coy with their magazine subscription deals. It's not like anyone is going to go to the site and say, "Awesome, I was just thinking how much I wanted to pay $40 for a subscription to FLEX magazine!" and then be all surprised when they discover a promo code that makes it $3. I just don't get it.
Anyway, you can get a 1-year subscription to FLEX magazine for $3 using promo code FLEX. You can buy up to a 3-year subscription at that rate, if that's something you're in to.