How much would it cost for my mom and I to eat at Olive Garden?

I want to take my mom out to eat for all she's done for me, but I'm on a limited budget. I'm choosing Olive Garden, vecause that's one of her favorite places. It's possible that she'll drink water, but she might want a soda. (I'll drink water if the price doesn't allow me to get a soda). Neither of us are big spenders, and if we see a good deal, we go for it. I want her to get what she wants without having to worry about how much it is. So again, how much would it cost for us, or at least how much should I bring?