Ken Foree (Roger) and Michael Berryman (Chives) are both well-known for their work in the horror film genre.
When Roger gives Steve the gas station attendant, a $50 bill, expecting change back, Steve says Roger owes him $6 more, because the gas has been raised from $1.23 a gallon to $2.63 a gallon. To cost $56 means Roger put 21.29 gallons of gas in his car. The original $1.23 price would've come to $26.18.
When Arthur throws the axe and Kel shouts "He could put somebody's eye out with that thing!" it's a reference to Ace Ventura: When Nature Calls.