A hit or toke of marijuana, usually in the form of THC concentrate via wax pen or Ooze pen in which the person providing the "smack" (hit/toke) gets paid a dollar in return. Fairly new, this term is most commonly used in high school bathrooms among vape kids, although you can find young adults engaging in similar activities at work or during hangouts.
Yo, you got dollar smacks, my guy?
Who got a smacker?