I have a bridesmaid who's mother assumes that I am paying for her dress and her son's (2) tuxedo's for my wedding, I don't have that kind of money, is it alright for me to tell her to pay for her own items?

 It is customary for the bridesmaids and groomsmen to pay for their own attire, although a bride/groom may volunteer to help with expenses if they are able. If it is too great an expense for the people you have asked to be in your wedding, and you are also unable to help with the cost, allow them to graciously decline and select someone else. Or, if this isn't an option, consider less expensive bridesmaids' dresses (off the shelf dresses) and/or suits (which they probably already own) vs. tuxedos for the groomsmen. It is not essential that all attendants dress alike and a variety of colors can make for an interesting and beautiful wedding. If you are planning to give the bridesmaids and groomsmen gifts as thank you's, you may consider putting that money towards the wedding attire and/or giving less expensive gifts.