if you state on a flyer no refunds on deposits are you obligated to pay

The problem that you have, if not legal, is your credibility.  The concept of No Refunds is if THEY cancel, not you.  The risk of not getting enough seats filled should be your business risk, not your customers.  The cost of the bus, even with less than all of the seats filled is likely less than you risk losing by canceling and a LOT less than you would likely lose when, not if, people start to sue you, even worse is when it gets out that you did this to people, people will not trust you again. You should refund all the money or give them the option to leave the money with you and apply it to the next trip, perhaps with some kind of additional incentive.  If you can't give them the money right now, let them know what happened.  Don't let them think that you abandoned them.  I would rather hear that you are short on cash and are going to get me my money back than dead silence.  People go to attorneys when there is dead silence.