I gave my new foster sister a pair of old ripped jeans to show how I felt about her
Did she get upset about getting ripped jeans from you?
What do you think? she got the hint.
While it's a nice gesture to give your sister a gift, she is likely going to be very hurt that they are old and ripped. She may think you don't care about her because of the state of the jeans.
I'm just giving her a pair of jeans. What is the big deal? I'm being a good person by giving her a pair of jeans.
It's understandable to not always be able to afford to buy someone a gift, but you should still make sure whatever you give is in working condition. It sounds like the jeans may not even be usable with the state they are in. The gesture was nice, but make sure the gift you give can actually be used.