All online fx brokers provide a free charting program of some sort in order for clients to trade. Some brokers develop their own charting program and isn't available at other brokers. Many brokers also offer/advertise 'pay-for-use' charting programs.
Brokers purchase
MetaTrader from the developer MetaQuotes, and provide it 'free' for both
demo use and 'live account' trading, so no, one doesn't need to purchase MetaTrader or pay a monthly fee to use the program.