Just a word of warning about buying cheap stepdown transformers off Ebay. The cheap ones are not Isolation transformers!!! Also they do not have switching power supplies, as someone suggested, as they are AC to AC only.
A isolation transformer is a normal transformer with a primary and secondary insulated from each other. If a winding fails the insulation will protect the 240 volts from getting on the secondary.
The cheap ones off Ebay are what are known as an auto transformers. They have one winding only, with a 120volt tap half way. Now twice the current is going through the 120 volt side of the winding. This is the part of the winding then that is most prone and most likely to fail. If it does fail you will end up with 240 volts on your 120 equipment.
If you buy any 120 volt equipment then always use a more expensive Isolation transformer - Jaycar sell them. Jaycar do sell one small auto stepdown transformer, but it has overheat and overload protection, plus they give a warning that it is not an isolation transformers.
Personally I would not buy any cheap ones off Ebay, because they probably have no protection circuits, thin wires and if you accidently overload it - then you are buggered!! When I did electronics 40 years ago I was always taught such transformers were very dangerous - just don't touch them.
Just a warning - only buy isolation transformers!