I've seen this for trademark maintenance fees. They send an official-liking letter saying it is time to file required paperwork and pay fees, which is true, but

I've seen this for trademark maintenance fees. They send an official-liking letter saying it is time to file required paperwork and pay fees, which is true, but they charge double to do what you can do yourself in five minutes on the official USPTO website. Services like this for getting a copy of your birth certificate, too. Basically pay to access the freely available form from state websites.