She just bought
a bunch of trash bags
EDIT : 2nd answer for fun (solely based on the fact that there is a "situation" tag. Be prepared for a really convoluted answer)
jenny was buying
time
because the situation is the following :
Jenny is friend with Alice and Bob who don't know each other. She thinks that the two would be a perfect match so she arranged for them to meet. In order for the two to break the ice, she decided to leave them both alone for a short time, so she pretexted to go buy something. She just took the first thing that she saw in the shop (which happened to cost $6). But once jenny got out of the shop she realized that she bought something really useless and just threw it with the trash. Unfortunately, Jenny's plan miserably failed because instead of getting to know each other, Alice and Bob just spoke about Jenny's weird behavior.