Surprised nobody else has said it: the cheap bottles by Evenflo and Gerber! They are easy to clean, super cheap, and the parts are compatible between the two and with Medela pumps and accessories. My favorite are the 8 oz glass Evenflo bottles that I bought a set of 3 for $5.99 at KMart, with a pack of 4 extra nipples for $3. Just be careful as the 9 oz Gerber bottles come with medium flow nipples. The bigger Evenflo glass bottles came with slow flow.