I have mentioned T-Post a few times in the past. It is a subscription-based t-shirt shop. You subscribe to T-Post and every month they send you a t-shirt and take money from your account.
They are now offering a free t-shirt to new subscribers. The first t-shirt will be free and then if you want you can cancel your subscription. Sounds familiar. Like extra services on your mobile phone plan that you don’t really need but are free for the first month so you accept them anyway. I just signed up for internet and got two months of free satellite TV but am contractually obliged to pay for the 3rd before I can cancel.
I think the concept is the same. They hope you either really like their service and won’t want to quit after the free period is over or they hope you forget or are too lazy to cancel so they can get more money from you.
Either way though, if you are careful you can get something free for a while and if you like it enough to continue paying for it it is not a problem either. I don’t know how long this offer will be open for.