Blue tarp? Go to Home Depot, get a large blue tarp, some roofing nails, and some 12' x 2" x 1/4" strips of wood--I think it's called furring--ask them to cut it into 3' lengths to make it more manageable. The tarp goes down, then the wood strips get nailed on top of it to hold it in place. Total cost for the temp repair will be under $100.
We sent this "roof-in-a-box" to a friend in J'Ville from NJ after Hurricane Jeanne came through. The brother of a friend of a friend was recruited to go up on her roof and install it. It held tight until almost three months later when the roofer came.
Anne