
Bathtubs range from $7.99 (for a bath sling) to $40 (for an infant tub—with a built-in digital thermometer—that allows "dirty" water to drain and fresh water from the faucet to circulate as baby bathes).
Here are a few types of tubs you'll see on the market:
Basic tubs that are flat on the bottom.

Tubs with a foam-lined, contoured interior that allows a baby who can't sit up to relax in a semi-upright position.
Tubs with internal nylon mesh support slings featuring padded headrests that cradle newborns.
Inserts that don't include a tub—they're little more than a sling that can be used in a baby tub and a sink to prop your baby up.
Tubs designed to fit in the sink, and then convert to a tub that can be placed in a regular bathtub when your baby can sit up.

Tubs that are designed to fit in a regular tub from the start.
Tubs with many of the above features that fold for more compact storage.
There are also inflatable tubs that fit inside a regular bathtub to give your baby a padded space to bathe in, but we don't recommend them because they can be dangerous. Parents might put them into a regular bathtub with water in it. The inflatable tub can then float and tip, spilling the baby.
These are designed to be used us a regular tub by a baby who is able to sit up. We do not recommend them. The seats present safety issues and can induce a false sense of security, leading parents to think that they can turn their back on the baby for a short time.