how can I avoid
You can use a VPN if you want, but then you will be identified as a VPN user. Many companies record VPN IP addresses (it's easy to identify them).
Another option is to use something a VPS and create your own VPN with it. It's much harder to see that you aren't a normal user.
Either way will cost you money. A VPN is easy to use but a VPS is more difficult if you aren't computer savvy. If you use either, it's really easy for law enforcement or some other government agency to trace it back to you.
It's very difficult to be traced if you are using Tor, so you have to ask yourself if your anonymity is worth the annoyance of being seen as a Tor user.
what should I do in TOR so they can't identify me as a TOR user?
You don't. If you use Tor, you will be using a Tor exit node and the website will see that.