There are so many good broadheads on the market, and some of those are really great ones. Just as with bullets, most broadheads are made to handle deer sized animals with no problem, so you can pretty much take your pick of the standard broadheads and do fine.
It is when the animals are big and tough to kill, or (less so) when the bow is marginal in its power, that the super-premium broadheads can start making a big difference. For instance, Burnsie has just mentioned Silver Flame broadheads. With a 50 pound bow and good arrows tuned to the bow, you don't need a $35 broadhead to kill a whitetail deer. An inexpensive broadhead that costs $5 will get the job done just fine if it is one made from reasonably decent steel that is properly constructed. Using that same 50 pound bow, the Silver Flame may hold up better when hitting the rib of a big elk, moose, grizzly or some of the big African plains game (which involve much more expensive hunts that also help justify expensive broadheads), but no one actually needs a Silver Flame to kill a deer. On the other hand, there are people who simply must have the best, regardless of cost.
For hunting really large, dangerous game, a super-premium broadhead is almost a necessity to most hunters to assure the greatest probability of maximum killing performance. For Cape or Asiatic buffalo, I now will choose to use either a Tuffhead or a VPA broadhead, because I know they will penetrate well, maintain sharpness, and hold up to heavy bone strikes. Other premium heads I have used failed under some of those circumstances. I have not used Silver Flames, but know others have had good experiences using them on the largest game animals. I have used the ABS Ashby heads and found them to work well but with more damage to them from being shot into animals than what I choose to tolerate for their high price. Other people have had some unfortunate experiences with the Ashby heads in the past, perhaps related to heat treatment of certain batches. They're very good heads, and I like them quite a lot, but they cost far more than a similar VPA or Tuffhead, with both of those less expensive heads, in my experience, working as well or better and holding up better under the hard hits that are commonplace when shooting animals that weigh a ton or so.
Most of the time I hunt deer or hogs, I shoot less expensive heads like Stingers, Hellfires, Tuskers or some other fairly inexpensive broadhead, and I have had no problems with them, other than the failure of a Bear Razorhead years ago that hit a big buck's shoulder and failed to penetrate. With a heavy VPA or Tuffhead, the broadhead would have been fine, and I might very well have had good penetration, but the Razorhead was no match for the bone. With the comparatively reasonable cost of the VPA and Tuffhead broadheads, there is no reason not to shoot them routinely, as some folks do. Losing them is much more of a problem than damaging them beyond re-use. And if you inadvertently hit something hard on a deer or a hog, you still have a decent chance of getting into the vitals.
Allan