Can I get a re-entry stamp on a 60-day tourist visa in Thailand and extend my stay?

Re-entry permit is 1000 baht for single entry to ‘keep alive’ your current admitted stay, not to add some more days. You can buy extension of 30days to your current stay for.1900baht. Maybe you mixed up these.

Depends on how long you're going home for. I wouldn't do re-entry permits on SETV because you can just get a new one for a fresh new 60 days when you come back for the same price. Instead of paying 1000฿ to just have a few day (now you have just 30 days left) so you'll be limited when you return and you need to leave again and get a new one anyways. If you only plan on staying 30 days and traveling again take advantage of the free 30 day visa exemption stamp and get the SETV. If staying in Thailand more than 30 days. Plan your trips around 60-90 days if on a SETV.

1000 baht for re-entry permit. It does not pause your visa so the admitted until date remains the same. So... if you'll have 30 days or less, better to just leave and come back in on visa exempt if you're eligible.