Most MT4 brokers offer demo accounts, as do some non-MT4 brokers.
You don't have to do the full screening of potential brokers for this Just find a broker (or 2 or 3) that's not scam rated and that doesn't demand too much info to download the demo. Set up a separate Yahoo or Gmail account for this if you have to give an email address. Don't give your real name, address, or phone number. If you do, many brokers will start calling and pressuring you to deposit. Some wll offer to "help" you to trade. 99+/100 times, that's the path do doom, so don't give them a chance.
Some brokers give choices on amount when setting up a demo. $5000 is the standard amount. Unless you plan to use $5k when you go live, try for the smallest amount you can get without having to talk to tech support.
Some demos will expire quickly. Others will keep running for some time if you keep them active. If you want to keep all the trading records from the demo as part of your learning process, the safest thing to do is to save a full statement at least once per week. I've seen long running demos get wiped because the broker decided to change servers.
Realize that although the price feed may be accurate, a demo account doesn't care if you trade 0.1 lots or 1000 lots during quiet markets. If the price is valid, the trade will execute as long as the account has enough free margin to permit the trade. A real account would have more slippage and requotes if you tried to make a large trade during quiet markets.
The other big limitation is psychological. If you find a demo account losing, you are much less likely to panic and break your trading rules than with a live account.
