Short story: guy dies and estate pays to clear out his place.

I found a near mint 1960s Tag Huer Sebring dash mount automatic timer. Sucker still works, in original box, with original warranty paper.

Anyone know what these really go for and where to sell that isn't fleebay?

If it is 60’s it is probably just a Heuer, Tag acquired Heuer in 1985 so previous to that it would have just said Heuer. They are collectible especially with the box and papers but not at the prices the watches command. You can go to the vintage section here https://tagheuerforums.com and post pictures to get info about value. They also have a marketplace. Post some pics here before you sell it though!