The boppy seems to be one of those essential things that every mom needs to have. Its primary purpose is for a nursing pillow, but I didn't really care for it for that reason because the baby tends to fall inward. A normal pillow seemed to work just as well. If you feel you need a good nursing pillow, I would recommend the My brest friend pillow, the lactation center at our hospital had one that I tried and it was nice, but not worth the extra money and storage space t me.
We did however use our boppy for other things. I used it while pregnant. I am a back sleeper and since it is recommended that you sleep on your side while pregnant, it was a hard adjustment for me. My shoulder would hurt from the pressure put on it, so I replaced my normal pillow with the boppy so that my head would be propped up and take the pressure off my shoulder.
We also used our boppy for tummy time and to prop him up when sitting just before he could sit on his own. If you are willing to get these used, I would recommend it. They seem to be everywhere at garage and mom2 mom sales, so you should be able to get one for $5 or under.