GameStop will sell single copies of the magazine in their store for full cover price, but as far as subscriptions go, I think you have to sign up and pay for Power Up Rewards ($14.99 / year). I've seen them offer renewals as coupons to use your points to renew your subscription, so if you can find somebody that has redeemed points for a coupon you might be able to get a little better than $15.
A lot of the paper magazines have either gone bankrupt or turned to digital. Amazon runs promotions for magazines all the time for $5/year (stuff like OXM, PC Gamer).