There's not much sense in using intermediary, third party payment-processors (like Skrill) to transfer money in/out of a forex brokerage: all that can do is produce additional delays and costs, unnecessarily.
You can't trade without having a bank account anyway, and directly to/from a bank account is the fastest, lowest-cost and most reliable way.
If the bank charges something or exchanges into your local currency at a rate you don't like, you're still going to incur that problem anyway, by getting the money back via Skrill, but with Skrill's fee on top: you can lose something by using a third-party processor, but not gain anything. (And many banks will let you open a USD account anyway, wherever you live.)