By Mike Rush

ST. LOUIS (KSDK) - It's sounds like a great effort: raising money to buy books for sick kids at St. Louis Children's Hospital. But there's one thing you need to know if someone comes knocking on your door:it's a scam.

Kim May has a receipt showing the $20 she gave. What she doesn't have is any sort of confidence that money will actually be used to help sick kids.

May says a young man and woman in their 20s came to the door of her Moscow Mills Home in Lincoln County.

She says they told her they were raising money to play in a soccer tournament in England, but also to buy books for kids at St. Louis Children's Hospital.

But the hospital tells 5 on Your Side's Mike Rush it's not part of a fundraiser like that.

The receipt says the company is called "Fit for Life" based in Colorado. Rush called the number, but got busy signals.

The hospital says this kind of scam pops up every year right around the time the weather starts to warm up and Newschannel has done similar stories in the past. A hospital spokesperson talks about what you can ask for to verify a fundraiser is legitimate.

"We provide them with an authorization letter that has our logo, it's on our letterhead and has my signature on it, so it provides some sort of assurance that this is really a legitimate fundraising opportunity for Children's Hospital," said Suzanne Fontaine, a hospital spokesperson.

May wants to warn others about this scam that tugs on your heartstrings to make you open your pocketbook.

"To lie is one thing but then to bring, you know, already sick children into it and turn that into a lie, it's just unforgivable," said May.

Children's Hospital does benefit from fundraising, everything from large events like Pedal the Cause to kids' lemonade stands.

Not everyone will have that authorization letter, so you can always call the hospital to verify or donate directly to the hospital.

We have posted a photo on our Facebook page for you to share with friends and family that explains 4 simple steps you can take to make sure you don't get taken by a door-to-door sales scam.