As a host for both Helpx and WWOOF, I ask that anyone using those services do not treat them as free. It can cost dearly to host someone, especially in a remote area where they have to be fetched and then returned to some mode of transportation.
There are lots of opportunity for fantastic experiences, for both the host and the volunteer. There is nothing worse than having someone waste my time and energy by taking advantage of the situation, and behaving as though it is a vacation. Only use those services if you have the intention and integrity to be productive and self responsible. It is NOT a babysitting service...it is a job and has basic commitment levels to fulfill.