It's a good idea, maybe OP has to try VPN over Tor. Connecting into VPN first to cover the Tor exit node. Let's do that experiment with free VPN and change all credentials when login success.
I assume you'll use the VPN first, and then Tor. This hides the fact that you're using Tor from your ISP. The forum will see the Tor exit node, not your VPN.
Connecting to your VPN server first and then to Tor is "Tor over VPN", as opposed to the other way around for "VPN over Tor" as DroomieChikito is talking about it.
Connecting to a VPN first and then to Tor doesn't add much to your privacy, unless as you say you want to hide your Tor usage from your ISP. This can equally be achieved without a VPN at all by using Tor bridges and/or pluggable transports. It may be worthwhile doing if you trust your VPN provider more than Tor, and were worried that a malicious third party could control both your entry and exit nodes to the Tor network. In terms of the evil fee, this set up makes no difference as your IP address will still come from your Tor exit node.
Connecting to Tor first and then to your VPN negates the whole point of Tor, as I explained above. It could potentially help with the evil fee if your VPN server's IP address is considered less evil than the Tor exit node you are using. Just as you would have to try multiple Tor exit nodes and are unlikely to find a completely clean one, you would also have to try multiple VPN servers and again are unlikely to find a completely clean one.