[T_I_N_A20]

My brother called me a few minutes ago telling me that it's Christmas soon and it's time to buy my little sister a present. He mentioned my cousins are coming from Toronto which doesn't make any sense as to why he told me that it's time to buy my little sister a Christmas present. He asked me to split 50% of the gift so it will be from both of us. I didn't want to pay because I don't plan on giving anything for my sister this year and he was in the store when he saw the spongebob square pants game for 18.93$ not included tax. It's not expensive but I didn't plan on any purchases and I don't want to pay. I don't want to be cheap or anything but with my brother, he's more of an instant gratification type and I remembered a year or two ago that he asked me to split the cost of the 40$ flower plant for my money for mother's day... Well my mother let the plant died and it was a pure waste of my 20$. I don't trust my brother on his purchase anymore. Still, I feel so bad if I tell him I don't want to pay half of the present for my sister because I feel like a scrooge for not giving anything to her.

What would you guys do at my place? My brother is currently looking for the present and he might call me when he finds it. I want to give him an answer if I'm ready to pay half for it but I keep giving in with his constant nagging... Arrg.