Hi, I’ve had similar requests, most of them from acquaintances. Generally, I enjoy helping others and always encourage a nice conversation. As someone previously replied, you can simply state your going rate, or refuse. It really depends on you. Some of us are social butterflies and enjoy a good chat anytime one comes around. Some of us are consumed by making money and only look for flying dollar signs.
Anyhow, I have a few friends who ask for help with their English, and as a good friend I almost always do so. If I’m too busy, or feel the request is something I’m uncomfortable with I tell them. But I also look at this as a great opportunity to share in the experience by letting them help me from time to time with my language questions.
I guess it all depends on how you feel about others asking for these favors or services. If you’re looking for friends, this can be a great opportunity. Or looking for a language exchange partner? Free lunch for your help? The possibilities are nearly unlimited.