I have a friend who is kind if poor?

I know I'm going to sound like a *****, but I don't know what should do. See I have this friend who is kind of poor and she doesn't like to spend money when she gies out. On the other hand, whenever I do go out on the town, I like to go all out with food, clothes, etc. The two of us are somewhat close and we tend to hang out a good two times a month. Still, whenever I go out with her she says se won't go to anyplace expensive and she won't even take any time to enjoy the finer things in life. I was wondering whether I should invite her to a day in Chicago that a group of my friends and I are having. Were going to have lunch at this slightly upscale place called kiki's bistro and then we're going to shop and go to the beach. Should I invite her? I feel like she would be a party pooper but I also don't want to be a bad friend.