VPN won't help you much trust me, if the security agencies of your nation wanna find you; VPNs can't do much.
I sincerely think that running a dedicated tor node for the purpose will be better than spending money on VPNs.
The problem with the TOR network is you need to have more users using the network if not any government or agency monitoring the network can pin point you. In fact VPN is much safer in that aspect and if you are too scared about it you can use both TOR and VPN in tandem which will give you a much higher privacy.
While trading it depends upon the exchange i decide on using TOR or VPN.