This is an antoninianus with Roman emperor Gallienus. The inscription on the front gives the emperor's name explicitly. On the back the inscription LVBENTVS (or IVBENTVS) seems to be somewhat a mystery as to meaning. Google translate says IUBENTUS means COMMAND, while some numismatic pages talk about 'youth of the empire.' The usual Latin word for 'youth' was 'JUVENTUS'. Experienced numismatist Curtis L. Clay has noted that there is also an issue of Caracalla with the word 'IUBENTAS', concluding that 'LUBENTUS' is likely an eastern mint error for 'IUVENTUS' made by an engraver unfamiliar with Latin. This makes sense for an engraver speaking Greek as his native language (the B, or 'beta' in Greek makes more of a 'V' sound.) In any case, it is a somewhat rare piece with values roughly:
worn: $50 US dollars approximate catalog value
average circulated: $100
well preserved: $180
Requester Marty's coin appears to the right. It is in great shape and would probably fetch $80 to $100 from a collector eager to add it to his or her collection.