Hi, the cheapest way for you Wofogg is to get your own unit done, if it's only the cam belt as you say &depending on the damage, if the valves that have hit the piston then you are talking money & as you say a replacement, what speed were you travelling when the belt snapped? if at a slow speed you might get away with Knacked unit, If you are Mech minded or you know someone, try putting a socket on the Crank Shaft end & see if you can go the full turn slowly, take the plugs out first this in-turn will lessen the compression, if you get a full turn ( I hope for you, you can, you may get away with a Head Skim & pressure test then the rebuild.