F.B.
If its simply seating temporary seating that you are after, I've seen some clever things done with garage sale wood chairs, which are stripped, cut down, and bound together with a long plank of wood across the seat and the back to form a bench.
seats can be padded out with a single long pad you can make out of cotton batting. http://froufrugal.blogspot.com/2011/08/bench-cushion-fail...
good luck to you and yours,
F. B.