Ok, but you also need a data plan to go along w/ it (or regular visits to top up; is that still a thing?), plus hide it from parents, or you're going to have a bad time.
Drugs are a different story. You can often get drugs from friends (free to start), can buy them a little at a time, and you don't need to stash any at home. For a phone to be useful, it needs to be readily accessible, which means you'll have it with you everywhere.
It's possible, but it's going to take a fair amount of work to hide a phone from a parent who's paying even a little bit of attention.
The real problem here is parents. Parents need to step up and do a better job. Source: am a parent.