Income or wealth disparity, much as we may hate to admit it, can make it hard to make friends and cause conflict within existing relationships.
Talking about money is part of showing vulnerability to your friends. You have to challenge yourself to be vulnerable if you want a deeper friendship. If you're never vulnerable with the other person then you should think about what type of friendship that is.
Money is an emotional issue; you should be able to talk to friends about it and for them to hear you out. Taking that risk might actually strengthen the friendship.