If you're going on a tour then you don't need to waste your money on stupid electronic translators. Better to spend your money on a Chinese translator in China then an electronic translator. Go to Craigslist.com, on the right hand side, look for China, click on it, click the cities and brings you to craigslists of china, on here you can look for "services" and most likely there'll be Chinese translators that speaks English and Mandarin or Cantonese or Shanghainese, depends which province you go and they are for hire. Email them inquiring their services.
If you're traveling by yourself and don't speak the language, most likely you'll be taken advaneforum.xxxe off in the way of paying a little bit more for everything because you're a foreigner and if you're caucasian you're an easy target. Most chinese people will not take advaneforum.xxxe regardless if you're a foreigner or not, these are hard working people and they love to help those in need. Very rarely will you run into trouble, getting scammed, etc. it does happen but just use common sense and don't trust anyone.