From what I understand, if you get a special deal on promotion and want to cancel, it's subject to a cancellation fee given you got a discounted rate right off that bat.
There is no return policy with these services unless there's a technical issue, which they would try and resolve. Simply not liking it (or not being able to afford it) is not an excuse they'll accept without a penalty or cancellation fee.
What you're asking, doesn't exist as people would just sign up for 30 days then cancel, repeat ect, they're not stupid. No company now a days will let you take advantage of a promotional offer than cancel it without penalty, the whole reason you got such a deal was because you signed a set length contract.
"I thought certain states had a buyers remorse law"
With cars or houses only before 3 days of purchase, not television or cell phone service.
It does not depend on the state direct tv has uniform policy for all customers, promotions can vary by state, generally not policy such as cancellations.