Register using a different connection/IP or you can try your luck with an unknown/less popular VPN providers (might work [50 - 50]).
Following this guide will help you on creating an account in bitcointalk but if you want to quickly remove the proxy ban then you should pay btc and your account will have a title called Copper Member in which a newbie will be able to post images and more but if you don't want to pay then follow SFR10 guide.
I think the forum is automatically suggesting how much you can pay to remove the proxy ban.
Look at this image below.
And I think the required fee for proxy ban is smaller than upgrading to copper membership.
Check this
https://bitcointalk.org/index.php?action=credit;promoteSo, paying the required small fee is enough to remove the proxy ban.