Buy one of those plastic discharge adapters and just screw it against the vent. You should have 2x4s around the eaves vent and should be able to just fasten it on an edge. Clamp or zip tie hose in place. Or if money is that tight you can always just screw the hose itself to the wood. Use washer to give more holding strength. A washer can be any flat item, piece of wood even.