Fait à compli

Ever get those nasty little cheques in the mail, that claim to give you $1.00, $10.00 or $20.00 that hook you into a service in fine print? That should be illegal. Talk about a quick dup. It's a farce really, why is if i endorse these cheques to redeem the cash, they are legally allowed to charge me 100s of dollars per month for a service I'm not particularly clear on?

Term life insurance - do they actually do what they claim?
Auto insurance - how do you give me auto insurance without my VIN, Model and Make of my car?
Home insurance - how do you give me home insurance if you don't have my address recorded somewhere?

Honestly, this is a mild form of mail fraud in my opinion. Why is it legal? and Why can banks get away with this too?