I like letting players hang themselves. Example:
* Buy spell components from Exalted Order of Arcane Peers at 10% above listed value, but guaranteed quality.
* But spell components at 50% off from Baldorf Half-Heart, but 10% chance they turn to dust, checked each time of casting.

— Mike Mearls, but Spooky (@mikemearls) October 21, 2018

Dusting ruins the casting of the spell, and if required use of a spell slot it is expended without effect.

— Mike Mearls, but Spooky (@mikemearls) October 21, 2018

As a DM, I love this kind of thing because the players know what they are getting into, it offers a meaningful choice, and you know that players will take that 50% off every single time.

— Mike Mearls, but Spooky (@mikemearls) October 21, 2018

Are they aware of the side effect, or is it presented as a “sketchy deal that’s being pushed hard”?Yes, I’d tell them the risk assuming a character was a caster or proficient with Arcana

— Mike Mearls, but Spooky (@mikemearls) October 21, 2018

Question: When I DM I generally don’t have players upkeep expendables (aka spell components, arrows, etc) because to me, it makes the game feel more meh to me in a way. Your opinion? Am I allowing them to keep too much gold? Or any other thing you can think of. (1 year DMing btw) I typically don’t worry about it, unless it’s for expensive stuff worth tracking

— Mike Mearls, but Spooky (@mikemearls) October 21, 2018

Then the player who took the Charlatan background begins selling stuff from Baldorf claiming it’s from the Exalted Order, for 25% more than Baldorf. Begins making profit, tarnishes reputation of the Exalted Order, and then the Order starts being devalued. My kind of player!

— Mike Mearls, but Spooky (@mikemearls) October 21, 2018