I understand that there are already a few guides on changing proxies in this forum, however I feel that some of the guides may be rather troublesome especially when you are trying to create multiple accounts on different ip addresses.
That's why I'm recommending a few proxy changing programmes that are safe and free of charge.
Personally, i have tried each of these programmes in the past to bypass school block sites and they are rather reliable >.<
Advantages: (Each of these programmes have an arsenal of its on list of fast and reliable proxy servers which will allow you to alter your ip addresses many times with a single click of a button)
Disadvantages: (You will have to download it/ May take some time to figure out how it works)
1) Hot spot shield (Free with ads)
2) Tor browser bundle (Free)
3) HIde ip easy (This is a paid application/ however there's a trial version available)
I have a cracked version of hide-ip easy but I am not sure if im allowed to post a download link here...
So before you use the programme, you can check your ip address here,
After using any of the programmes above, to be safe, check that your ip has changed to a different one,
To be safe, while using the programme, you should also clear the cookies on your browsers just in case.
Hope this helps - My first mini guide =)