Natasha asked me today about what to bring as gifts for the families with which we will be staying. Good question. It is not obligatory to bring a gift, but it is a nice way to thank people in advance for their generosity in taking you into their home, and to start things off on the right foot. I don't know the details about your homestays, so I don't know, for example, if there will be children in the family. If you are really eager to know, you can contact Lee Cridland (firstname.lastname@example.org) at Bolivia Cultura for more information.
Some appropriate gifts might include:
• hand towels or bath towels
• kitchen items
• books and magazines in English
• small hand tools
• toys for children (even if none live in the house, they will know people who can use them)
• baby clothes
• clothes for adults
• other small items for use around the house
Generally speaking, I am not the best person to give advice on being nice. Your mom might have additional insights into this topic.