How much to charge for playing the violin at events?

It's all about how much you value your abilities. You can never be expected to do it for free being you have expenses to cover. Do a search for violinists online in your city/state. Find their prices, or just simply email and ask them that they charge, never letting them know you are a violinist. We have been photographing weddings for over 25 yrs. now; www.charlestonphotovideo.com, and we ALWAYS take photographs of the musicians. Try to get some professional photographs taken and get your own website going. This is the best as cheapest advertising in the whole world. However, as always, competition is the best way to judge your fees (along w/ your abilities and experience)!!