For about $35, you can get either of these KaBar Becker neck knives (shown in varying stages of newness / customization). As far as I'm concerned, this is the ideal size for cleaning deer. Also use them all the time for ... whatever you need knives for. I have larger knives and smaller but man, are these useful.
New (BK14 on left and BK11 on right)...
Unwrapped BK11 with freshly cleaned doe...
Wrapped and stripped (well - BK11 is stripped)...
Becker family picture. Thats a BK14, two BK11s, BK2 and BK9...
Can't go wrong with Becker. By the way - if you want the perfect all-around camp knife, BK2 is (IMO) the answer. It wouldn't be my top pick for cleaning game - though it obviously could - it's fantastic for general camp life.