In Dungeon World there is a special move called Supply with the following details:
When you go to buy something with gold on hand, if it’s something readily available in the settlement you’re in, you can buy it at market price. If it’s something special, beyond what’s usually available here, or non-mundane, roll+Cha. ✴On a 10+, you find what you’re looking for at a fair price. ✴On a 7–9, you’ll have to pay more or settle for something that’s not exactly what you wanted, but close. The GM will tell you what your options are.
Additionally there is a Thief advanced move called Connections with the following details:
When you put out word to the criminal underbelly about something you want or need, roll+CHA. ✴On a 10+, someone has it, just for you. ✴On a 7–9, you’ll have to settle for something close or it comes with strings attached, your call.
Now, it seems that if the players visit a tiny village that lacks a particular magical item, they could simply purchase it (or any number of magical items) via a good Supply roll so long as they have coin on hand. While this does have the obvious cost of the items' coin worth, it does seem to make a pilgrimage to a larger city with the intent on getting access to rarer stuff unnecessary.
Worse, Connections appears to allow the acquisition of powerful/rare stuff for free on a good roll! I understand as the GM I can limit these things via fiction, but do I really have to work against the stated moves' descriptions to do so?
Why wouldn't players just use Connections and a good CHA modifier to get amazing stuff repeatedly? What limits this ability (and to a lesser extent, Supply)?