You go and start looking for VPS providers and many of them look good. What is Special About Virtual Private Servers For MetaTrader Expert Advisors (EAs). The cheapest one you can find is about $27/month and they go all the way up to $150/month.
You are now careful and make sure they don't terminate your session when you disconnect. You pick one, install your MetaTrader and off you go... Everything looks OK now with this provider.
Then after a month of joice usage the system is down for a whole day. Soon you may realise that when you disconnect using your Remote Desktop client, they automatically terminate your session and stop the MetaTrader 4 as well. Once you have done your testing and become serious about using an Expert Advisor on MetaTrader, you would almost certainly want to host it in a reliable Data Centre so you can switch off your PC occasionally, reboot it when you want to install a new program or simply because you are concerned about the reliability of your Internet connection.