The Fisher Price Rock and Play is a product we highly recommend. It is a portable bed that can be used for naps or overnights. It holds babies at a higher angle and helps babies sleep more soundly. It seems to especially help babies that have reflux to be able to relax. The bed rocks (with parents help) and has a vibration feature as well. It will hold baby securely with its deep pocket. The rock and play ilightweightht and folds, which makes it easy to move from room to room or to pack into the car.
This bed is intended for babies who are not able to sit up unassisted. We have found that it usually works for babies up to between 5-7 months. Once baby is trying to sit up on their own, they need to be moved to a more stable bed.
In using this bed, I do recommend that parents switch out which way baby faces occasionally. I also prefer the padded version of the bed. It has been my experience that both of these things lower the possibility of baby developing a flat head or torticollis in most of the beds that they can sleep in.
This product ranges from $40-60 and is easily found at most baby or department stores.