Many brokers allow you to start trading foreign exchange with a very low minimum deposit or even no minimum deposit. Withdrawal minimums and maximums will vary by broker, but it’s not uncommon to find minimum withdrawal amounts of £50 or the full available account balance, whichever is less.
Likewise, maximum online withdrawals are sometimes capped at around £20,000 in one transaction, though again, you’ll want to peruse the limits on different brokers to find out for sure.