Looking at the website, it says that
"Reduced (18-24 years old) and Free (under 18 years old and other specified categories) tickets cannot be purchased in advance. In this case, buyers will have to go to the Archaeological Park’s ticket office to show their document entitling them to free admission (identity card or other document proving the right to free admission)."
If everyone else has tickets and we have 2 kids (10,8), can we go straight to the turnstile and show our passports there for the kids? Or do we have to stand in the ticket line to get a free ticket, having already bought all of them for the adults ahead of time? Thanks!