A block and tackle would be the cheapest option.. basically a simple pulley that gives you a mechanical advantage. Usually found for under $75. Motors are typically slow (both rolling and unrolling) and might be a bit overkill for a 40 pound load.
In the old days, a barn had a simple pulley crane system for hay bales. Same principle. But you do need a place to hang the pulley from. Some systems have an automatic brake in them which could be helpful as a safety device.