The ones I am are using are DropCam
You can get them at Walmart, Home Depot....few other places and direct
I use the Drop Cam pros and each camera is around $190 each.
Erik's Cameras sound like a great deal.
My cameras, the first one cost something like $10 a month to have up to 7 days recording available (can get up to 30 days for bit more money)
and each camera you add is only like $2-3 for the month additional
You can zoom via pinch and squeeze on your phone, they have night vision.
They ARE NOT outdoor rated and so my office window and shop driveway are inside....and no screens on the windows to see better.
I do get updates via my phone due to motion detection, or noise detection too via immediate notices through their app for my phone, and email on my phone.
www.dropcam.com