I like the schrade sharpfinger I think it's called. About $20 or so. I've skinned beaver, deer bear etc with it. For duck and smaller animals I like a very thin blade like a boning knife. A bit stiffer than a fillet knife but fairly close in profile. Check out some trapping knives. They tend to be pretty cheap, sharpen easily and if you do something bad to them are easily replaced. Someone else mentioned kitchen knives great idea! Most of them are decent quality and you probably can't find a cheaper quality knife than a kitchen knife. Personally I gut in the field and everything else gets done at home, usually on the tailgate of the pick up.
Not mentioned is the saw. I have one of those take apart Wyoming saws that I use really like it but you can get a meat saw at princess auto that has a bigger bow and more stroke for less $.