How much is this coin worth

How do you know it is real? I have some repro roman coins like that. Take it to a coin collector.

You might be reading it wrong.
S. P. Q. R. OPTIMO PRINCIPI.-- On coins
Of Trajan, Hadrian, Antoninus Pius, Sept.
Severus, Gallienus, Maximinus Daza, Alexand.
Tyran. Licinius pater, and Constantinus Magnus.