One of your friends is letting money issues get in the way of your relationship with them. Either they don't feel they can keep up with your lifestyle or they are worried you can't keep up with theirs. Either way, the two of you need to stop being afraid to talk about finances. You don't have to divulge details: but agree on the fact that spending time together is all that matters. How you spend that time together can be affordable and comfortable for both of you. Make it happen.