They've been doing it for ages,
It used to utterly piss me off when I was paying a subscription for both & getting nothing then walk in to a shop & see a free give away, even if one of them was usually un-sold stock from the previous month.

Great for the casual buyer and lets be honest it's a marketing ploy to draw those casual readers in to buying, once you get it on subscription they have you & your money on the hook.