Sometimes budget or desperation will lead a customer to purchase used equipment.
However you need to remember that even while well maintained and documented equipment commands a higher price, you still have no guarantee.
Public or online auctions commonly offer low cost used equipment with little or no history.
I have a customer who purchased a used compressor that “looked” good online. But soon after he put this bargain purchase into service he found out that the coolers were plugged. This lead to a high cost major repair before the first service was even due on the unit, and so it turned out this was no bargain.
Down time, labor, and parts added to the bargain purchase price ended up being almost as much as a new compressor. And a new compressor would have come with a warranty!
When it comes to material pumps the motto is the same. Used pumps are just that, used. They typically require a rebuild at minimum and generally are not the right configuration for an application.
Remember the old maxim – “You get what you pay for”.