I scour the Dollar Store for parts on many projects and I have use parts from the Dollar Store countless times.
Here are a few examples:
The Acrylic dome on my Konker Connection is part of a butter dish from the Dollar Store (The other part will likely be used to cover a solar panel on a different project):
This urethane orb was found in a Dollar Store. It was used in my LED road test.
This PLA dispenser for 3D printers was built with low-cost skateboard bearings and uses a paint roller for an axle:
The turn table in this Star Trek Alcove video is from a Dollar Store:
This tablet stand for my Star Trek Alcove uses a plastic hockey stick from a Dollar Store. That power bar was also a Dollar Store item.
The stand for the Purple People Eater also uses a plastic hockey stick from a Dollar Store:
The list of Dollar Store parts gets to be very long ......