LOL at buying tips.
Always cut a part of the rolling paper box and make a filter when I do roll.. it doesn't filter the smoke as much as keeping the burning ashes from torching my throat.
total head quit being a weed douche...
just grab some regular business cards, those are perfect... cut into little strips and rolled into a spiral.... its not meant to "filter" thc or tar... its meant to keep the end of the joint open and prevent weed from going in your mouth