The kid needs 5 € to get VPN. Mining xmr for that is inefficient. A logical question to ask (before explaining how to mine) is: do you really need VPN to begin with? Can’t you use a no-charge option instead? That’s why I asked that.

ExitNodes in torrc is a well-documented, official option of Tor, not a “hack”. You’re right, one should not use it unless really necessary. Example: you’re on Tor buying a digital gift card from proxystore with xmr; they ask your country; if you’re a EU citizen, you might want to say non-EU. When you do that, common sense dictates it’s better if your exit node is not in the EU, say in the US. When you redeem your “American” gift card, again you may want to play it safe and consistently use a US exit node in case they GeoIP you. When you’re done, you delete the ExitNodes & StrictNodes directives. Just one example.