You need port forwarding to be an effective seeder, and many VPNs do not offer this feature anymore. Mullvad was the most recent one to announce they're pulling port forwarding support.

So then, you're stuck with spinning up your own VPN, which pretty much means you're stuck renting a server from some cloud provider, which then have your info and payment information so any warrant would give you up. Could find a provider that allows crypto payment, but then it's definitely not $3/m. Not to mention bandwidth costs.