Depends what you want it for really. If it's to check whether deer, fox, poachers or herds of wildebeest are sweeping majestically past a certain point then the cheapest available will do. If you want good pictures or good video (most of them do video now) then you'll need to spend a bit more. I'd have a ratch on the internet and see what different spec cameras do and compare them against what you want from one. At night time I suspect no camera is going to produce pictures worth hanging on the wall, so it's really horses for courses.