Video Baby Monitor

I know several of you mentioned using video monitors for babies. What brands have you used? What do you recommend? Has anyone used a wifi camera?We're trying to decide what to do. Our funds are limited, but I really want a video monitor. We co-slept with all 4 of our babies so I have never had a baby in a crib, much less a totally separate room (no babies in parents' room with our agency)! Baby will be sharing a room with our 3 year old daughter down the hall from us. I think without being able to see baby, I'm going to be constantly checking on him/her in the night and driving myself crazy! So any suggestions on a video monitor that works well, but doesn't cost a fortune would be much appreciated! :)