Here’s reporting on the fentanyl crisis, covering who buys the drugs and why

https://youtu.be/925wmb-4Yr4

It's incorporated into pills that appear to be equivalent to prescribed opioids like Oxycodone. From buyer perspective it's just a cheap opioid pill.

It is typically laced into other drugs. A small amount of fentanyl is highly powerful, so if you mix it into heroine, you get a different buzz. But if you (a drug dealer, not a chemist) mess up and drop too much, then your customer will accidentally OD.

Tiny bits of fentanyl are added to a variety of recreational drugs used extensively by all kinds of people, rich and poor. They add it to cocaine, heroin, meth and even marijuana. They imitate oxy, percocet, vicodin, xanax and adderal using fent laced pills as well.

As much as 20% of Americans use these recreational drugs. Europeans on average use recreational drugs like half as much as Americans, maybe 10% use them.