There's lots of good concerns and great answers with all this, and you'll figure it out just fine. But one thing you should disregard entirely is the price of ammo.
Ammo is one of the cheapest things on your entire hunt - you'll spend more on food, on gas, on clothes, etc, etc. Find the load that you shoot best, and spend the money you need to maximize your chances of killing and retrieving that animal as effectively as possible. You owe it to yourself, all the rest of the money you put into that hunt, and to that animal itself.