I am looking for case law or legal opinion/ decisions in PA regarding verbal agreements

We paid a room deposit for our son and 3 of his friends to go to shore for seniort week. this was arranged in January or Feb. of this year. Approx. 10 days prior to their scheduled departure, we met with the parents of 2 of thos going. 1 parent gave us $200 to cover their share of room rental and cleaning deposit, the other discussed splitting gas and food costs and promised payment upon her son recieving his graduation gifts. 5 days prior to departure, both backed out of the trip and have refused to pay their share. we refunded 1 $100, and tried to find replacement travelers, but were unable to. The room needed to be cancelled at least 14 days prior to reservation date to recieve the deposit back. the other 2 boys were still planning to go on the trip and the 2 that backed out were told they were still welcome to go and use the room. we got stuck paying their share as well as our sons and have filed suit to reclaim what we spent on their behalf, approx. 149.00 each plus the court costs. the 1 party would only owe $49.00 plus costs at this point. Are there any legal references or case law in PA regarding similar situations we may cite?