I used a camera I got for $86 but not from wal-mart. I set it on a tree that looked at a stump that was getting shredded by deer going after some buck-jam I was putting on there. every morning the deer were at the stump but the cam never took a pic. the cheap ones are not sensative enough or something..... and then the cam got swiped!!!! IF I ever get another cam, it will be one of those 5 way locking jobs. They are big bucks but I won't have to worry about it getting swiped!!!!!
I have the Moultrie digital from Wal-Mart and they are not that sensitive. However on a differnet sight I found a solution to this. According to the poster, who builds his own, the problem is that lens is to far from the IR sensor. He gives step by step instructions to fix the problem, for under $5. I haven't done it to my camera but his claim is that it fixes it great. You basically have to replace that smokey lens that is on the outside, take out a washer that's behind it and replace it with a thinner lens, this puts the lends closer to the IR sensor which increases the sensitivity. Worth trying, I will try and find the write up on how to do it and post it here.