What is the ps+ trick?
As others have said you don’t need to use a VPN for PSN purchases. There’s been a lot of VPN talk on here recently and no idea why.
You need to change your US PSN address to a non-tax paying state.
It's currently on sale on the UK store for about £20.49 so it'll be a while before it drops to something like £9.41 over here. No VPN required and no-one's ever heard of a person getting their account banned (even Shuhei Yoshida admitted to having multiple accounts across different regions). This guide shows how. Just use PCGameSupply instead of Amazon for US PSN credit. https://www.nowgamer.com/ps4-how-to-buy-us-digital-psn-games/