I too, have used Intellus for a .99 search. I carefully read the agreement, and noted that I was signing up for a $19.95 monthly fee to look up any information I wanted, anytime I wanted.
After I received the information I was looking for, I immediately called Intellus to cancel my account. I read in the agreement that I had 7 days to cancel, but did it immediately.
So far, I haven't been charged anything, but I check my account everyday. When I cancelled the account, I made sure to write down the name of the person I spoke to, the date, and the time.