No such a thing as a great quality AND inexpenive in a camera or any other optic. Sorry, there is no inexpensive option if you want quality wildlife pics. Of course, it depends on your definition of inexpensive, but wildife photography is not beginner's photography, either in terms of the equipment or expertise needed.
Just about any kind of widlife photography is going to require high magnifications. This is traditionally the realm of SLR cameras with long (and expensive) telephoto lenses, but many amateur wildife photographers use small digital point and shoots mounted behind a quality, tripod
mounted spotting scope
(digiscoping) to get the magnifications needed. For the basics on digiscoping (taking pics through the eyepiece of a spotting scope), see my article at
Regardless, handholding little point and shoot digitals with 3x or 4x optical zoom isn't going to cut it for wildlife work.
Lastly, there is a world of difference in the magnification and equipment needed to fill the frame at 500 feet with something the size of a bird and something the size of an elk. 500 feet is an extreme distance for a bird photo. Best option is probably digiscoping - mounting a small digital camera
behind the eyepiece of a tripod
mounted spotting scope. Pic quality is going to be directly a function of the optical quality of the spotting scope
and price is always a good indicator of optical quality on a spotting scope
or a camera. Once again, no inexpensive way out on this one if you want quality pics.