are flat irons ok in carry-on bags?

In the US is ok to travel with your flat iron in your carry on bag, but is it the same in domestic flights in china? (its the only bag im going to take so i want to put it as a carry on bag)
Also if I carry a camera... normal one nothing fancy.. do I have to pay extra? im confused because of one of the posts here... its the 1st time i hear something like that.
thanks