republic airways benifits on united

I am a registered friend on the united benefits of my republic airways employee friend, and would like to know if anyone knows the charges for using United to fly nonrev. We were told it is 20 dollars a leg in the US and 50 international, but dont know much else, like are there imputed taxes, or does domentic include Canada, Mexico, Caribbean? Are there any hidden charges? It seems United doesn't bill the employee for several months for pass travel. Any help would be appreciated, thanks, Rob