two nights ago, a bunch of Mac mini's popped up on the Refurb store. I was viewing through my computer, and the config I wanted was the i5, 256GB SSD, 8GB Ram for $750. I didn't see that particular config there, so bit the bullet and ordered the i7, 256, 8GB Ram for $930.
Then I hopped on the Refurb store with my iPhone. ...and the i5 config I wanted was there - just not viewable from my iMac Safari browser. So I cancelled my i7 order, and ordered the i5 option through my iPhone. ...sure enough - it shipped the next day.
Talk about a weird anomaly. ...or it's done on purpose. Check the Refurb Store using both a desktop computer and a mobile device (iPhone/iPad). You might find what you're looking for.
The Mac mini's sell out quickly. The Mac Pros and iMac Pros? Not so much.