... There are many available today from basic ones to video ones!
WHAT IS IT?
The BT 100 Digital baby monitor has two units. One is the parent handet, which consists of a plug in adapter and mobile handset. The other is the baby unit which is powered by the mains.
The parent ... Read review
I believe simple AA batteries are all you need ... you can also use rechargeable batteries but these cost more ... probably more economic in the long run though... or you could just plug this into the mains..