Im not cheap, but I didn't want to spend three dollars plus shipping on bearings for the biowheel 150b, not to mention Drsfostersmith.com doesnt carry them for that model. I bought the filter used and it didnt come with bearings. Heres the solution. Take two tabs off of a regular 12 oz. Soda can, prefferably the Square tabs (A&W root beer tabs work the best, experiment and see which work for you). Get a small set of pliers and slowly and gently bend it in half at the little bar in the middle of the tab. Once you have it slightly bent, Use your fingers to bend it completely in half. Stick the smaller end (the part that was connected to the can) in the cavity where you would the bearings and VIOLA! I just saved you three dollars and shipping. I HAD to share this with you all. =] AND the best part is, if you lose a bearing, you can relax and have a soda knowing you dont have to go out and buy another one. Awesome. *note* im not sure if this works on the other models, although, through common sense. If it has a cavity for a bearing, it should. **note** for obvious reasons, the biowheel doesnt spin as perfectly smooth as it would if it were used with the proper parts and i have no idea how this would impact the effectiveness of the biowheel. It still spins but it has some hiccups. I've been observing it for about 20 minutes and it has yet to actually stop spinning, so, use at your own risk! =] Im only using this as a temporary fix so i can continue to cycle my filters and get the bacteria colonies up, i do intend on buying the bearings sometime soon.