I would do whatever you can to NOT make any quilts for this family member. The moment you make her quilts for "fabric only" you will be her go-to person every time she needs a gift for someone. Honestly, how many quilters have time to sew for others? I make quilts for my sisters since they don't sew and I love how they start crying when they get a quilt. But I would not want to be someone's cheap seamstress. A gal at work asked me how much I would charge to make her a quilt. Out of my mouth (too quickly) I said "no way". People who don't sew have no idea what a labor of love making a quilt is.
If you feel that you need to do this for your cousin, I would call her and tell her about how much a quilt would cost. I would tack on some labor charges and tell her you'll swing by to pick up a deposit so you can go fabric shopping.
Good luck on this.
Ellen