Why doesn't my aunt want me to meet her friends?

My aunt is always telling me how she and her small group of friends are always going around to the garage sales and thrift shops and all the bargains they find. I've been giving her some strong hints that I would like to be included in their forays, but I am never invited to participate. Once I asked my aunt directly to be invited. She just laughed nervously and changed the subject. I didn't think it was so funny. What could be her problem?