Yes, cheapest is coiled dark hose, like Carl uses or a batch direct solar hot water, cheapest way to do a batch solar hot water heater is to use a watertight hot water heater tank, doesnt matter if gas or electric, you want no leaks and free, so doesnt heat or previous owner took it out to put in a tankless. Paint it black, build a box, with glass on one side that the tank fits in, set out in sun, etc.... lots of designs and pictures and plans for this. If you can scrounge materials, it would just cost black paint, connections, etc....
http://casparinstitute.org/solarnet/IndHome/ch0206.htm this has a picture, just search "batch solar hot water DIY" or something
But, this and the last 2 comments should go to a new thread as they have nothing to do with washing machine review-- maybe a mod will move ? Split and moved.