Check out this awesome baby sink tub by PUJ. It's just one piece of soft foam that turns into a bathtub. Genius idea!
According to giggle web site:
Infant tubs are great for cradling slippery babies during bathtime, but if you don’t have room to store a plastic tub, this soft foam tub is a brilliant solution. It contours to the shape of any standard bathroom sink, but hangs and stores flat!
$40 - such a steal!