Tipping day tour guides for paid tours?

Yes Turkish lira. I'm questioning how much you tip in that currency

nothing, you paid for the tour why do you feel you need to tip on top of that.

Here is one opinion that sounds reasonable.

https://theturkeytraveler.com/tipping-in-turkey/#:~:text=In%20Turkey%2C%20it%20is%20customary,offend%20anyone%20by%20tipping%20more.

TOURS AND TOUR GUIDES
There is only really one area where tipping is expected, rather than appreciated, and that’s on guided tours. If you have booked an organized tour that comes with a guide, then most guides will expect a small tip at the end of the experience.

Of course, like always, the amount you give is dependent on the quality of the service. Usually, $10 USD per person, per day, is a good base to start with tours.

If you have taken a free walking tour, you might want to give only $5-$10 USD per person since it’s only a couple of hours. Likewise, if you visit a museum or historical site, such as the underground cities in Cappadocia, then you might want to offer up to $10 USD depending on how much you enjoyed the tour.

The driver usually doesn’t expect a tip, but if you think they drove well and took great care of you, then it’s polite to give them a small tip as a token of your gratitude.

Or less generous
https://turkeytravelplanner.com/details/money/tipping.html

Tips to guides and drivers on organized tours are at your discretion. Certainly guides and drivers hope for tips, but a good guide or driver will not think less of you for not tipping; and a bad guide or driver deserves no tip.

Remember, this is a tip meant to signify good service (if that's what you've received), not his/her payment (which you will already have paid by paying for your tour).

That having been said, US $20 to $40 per day from a small group would be appreciated by the guide, somewhat less for the driver.

This is the total tip for the entire group, not the tip per group member. So for a 10-day tour, the guide would be given $200 to $400 total from the group as a recognition of his/her excellent service.

or
https://theistanbulinsider.com/how-much-and-when-to-tip-in-istanbul/

Tour Guides — Tour guides don’t work for tips, you already paid for their service. Having said that, they of course do hope to receive a tip, which is token of your appreciation for a job exceptionally well done by the tour guide. Typically, people don’t tip the guide(s) individually, but as a group. Between 10-15 Euro is common.

Thank you for your responses.

Unless the "free" tours in Turkey work differently from the way they are run in the rest of Europe (which seems unlikely), tipping the equivalent of $5 or even $10 seems inadequate. The guide is charged a per-head fee by the tour company. Way before the pandemic Rick reported that fee was something like $3 or $4 (I don't remember). It seems likely the guides are being charged more today.

They might be happier if you tipped them in euro.

ponygirl813; same with me in the U.S.

They might be happier if you tipped them in euro.

Given the state of the lira, that might not be a bad idea.