Buy your cows and/or your herd bull. Buy the quality of cows that meet your standards, as far as having a good breeding herd is concerned.
Your herd bull should be selected to improve your herd, as he will be providing half of the genetic potential of your calf crop. Knowing conformation at this point will really help in determining how good a herd bull is needed. Fertility and live calves are key to profitability. One live calf is worth more than 100 dead ones. A bull that sires calves that are larger than your cow can safely give live birth to is economic suicide.