Drug users often take as a group, so if the group has no money to buy their regular drugs that day and one of them has heroin to snort or inject they will do it. That's how most addicts I met while living in a shitty drug filled area got addicted. Heroin is the cheapest street drug here right now too since it's cut with dirt cheap and easy to import fentanyl. For years it wasn't even illegal to export it from China, so anybody could get it direct off sites like Alibaba and try and smuggle it in.