The term 'obtain free' can be solved by the word 'SPONGE', which is a six-letter word. Sponges are a type of aquatic animal that live in the ocean and have porous bodies that absorb water. They are also used as cleaning tools, as they can absorb liquids and dirt. In this context, obtaining something for free could mean taking advantage of the SPONGE's ability to absorb liquid and dirt, thus obtaining something without having to pay for it.