This Riddle tho...

[Exit]

I need help solving this. I can't find a solution (I wasn't trying to cheat?) and thought maybe some of the brilliant minds here could conjure one up.

"While grocery shopping for her family, Shannon was having second thoughts about something she wanted to buy. She knew making the purchase was a mistake, but she did so nonetheless. It only cost her a couple of dollars, but because of the purchase, she ended up having to pay thousands more. What did she buy?"

You can do a google search yourself and find the original question in "One-Minute Mysteries and Brain Teasers: Good Clean Puzzles for Kids of All Ages". It's number 55. It's accompanied by a picture. An officer stands behind an empty cart to the left of a girl who is carrying a grocery bag in hand. She's passing this bag to another officer who is standing in the open door at the rear of what looks to be an armored truck. She says to him "Be careful." It may or may not be related to the answer.

I do not know the answer so I can't confirm if anyone's guess is the right one or not.

Some possible answers thrown at me from others...
A pet?
Signed up for a line of credit?
Eggs?

Link to the riddle.

Hint:
Nothing illegal was happening.

[Vilageidiotx]

Gum. Because allowing your teeth to rot can ruin your life forever.

[Darcs]

The answer's at the end of the book

[mdk]

Pregnancy test.

edit: Looked up the answer, and I like mine better.

[Exit]

The answer's at the end of the book

@Darcs

Yeah i tried looking and It wouldn't let me look at the solutions.

Pregnancy test.

edit: Looked up the answer, and I like mine better.

@mdk

And that was the answer I was leaning toward until i finally figured it out. I didn't look the solution up but a friend and I both agreed on an answer and it turned out to be right.