ANSWER:

You going there & buying the props, taking pictures and all this is not permissible in the first place due to such events having haram activities like music, free mixing etc.

Estimate an approximate amount & pay that amount to any poor or needy Muslim while repenting to Allah.

QUESTION: I went to a university festival years ago and there were props available for money. I used the props for taking pictures but due to a huge crowd we were pushed out of the hall and I forgot to pay. Can I repent to Allah or is it a must that I pay back, because I don’t even remember the amount now