Hi, does apple ever sell refurbished apple watch, series 5

There is never a known inventory of what they sell refurbished. You just have to keep checking the refurbished Apple website to see what (if anything) is available. Not sure when the last time they may have had a series 5. You can check authorized retailers too. I know Best Buy sells refurbished Apple Products for example (listed as Geek Squad refurbished. They are one of Apple’s Authorized Repair options which may explain why they are able to refurbish the products. That’s just a guess though). A quick search on their website showed they have some refurbished series 5 available

Refurbished Apple Watch Deals - Apple

However, just looked, and there are no refurbished Apple Watches current available.

There are web sites that will monitor the Apple Refurbished store for the product you want, and alert you when it is available in the Apple Refurbished Store

Google: "apple refurbish tracker"

and you should find some suggestions for monitoring the store.