it is very important to take cousine into account when shooting at distance. the ammount of error is greater than most realize.
that said there are ways to do it without spending large sums.
if your the type of hunter that moves around with a sporter type rifle, then the type that attach to the scope mount are very nice.
midway has one in their cataloug including the mount for under $150.
if on the other hand you dont mind doing some calculations and carrying a larger ammount of gear their are other options that work equally as well.
northern tool for example has a protractor that moves on its own for about $10. its very light weight, but is about 4" in diameter. a small inexpensive calculator that has the cousine feature is the only other tool you need.
you would of coarse need to know the distance before doing the calculations.
charts can also be prepared similar to elevation charts.
that way you only need the distance, check the angle, and look at the chart.
even guessing the angle is better than doing nothing.