Annoyed by sister-in-law

My sister-in-law insists on buying something for the baby, which is great and I told her she didn't have to but it would be appreciated. She asks me what we needed I told her I updated my registry because I'm using it as a shoping list for myself. I've already bought the big items I wanted so the only things left to get is bottle dryer, a few more 3-6month clothes, a few toys, teethers, crib sheets ect. Pretty small items. Well since the beginning she keeps mentioning a stroller carseat combo she bought her half sister. She said her sister loves it but she also has 4 kids ages ranging 6 to newborn. I told her I didn't really want a stroller and I already bought a car seat. I had a stroller with my other 2 kids (ages 9 and 6 now) I never used it. We dont have a mall or anything here so anywhere I go I can use the infant carrier, a cart, or get one of the lightweight 20 dollar strollers. She keeps pushing it. Its starting to annoy me, for the price of the stroller she could buy my whole registry, not that I want her to but to spend that money on something I've said I don't want seems like a waist. Why ask me what we need if your going to push to buy something else? She wants me to go by her half sisters to look at the car seat stroller combo....Starting to stress me out and seriously annoy me, i feel like telling her to not get anything at all and stop bugging me!