TK, if you are selling eating eggs, it doesn't matter what is in your flock, as long as it will lay eggs.
If you are selling hatching eggs, I suggest that you purchase the best purebreds that you can afford. If you don't have a lot of money, buy fewer birds.
If you've got an incubator, you can turn a trio of nice birds into 600 birds in one year. Then cull them down and that will be 300 hens and maybe 150 keepers. How many birds do you need?
For the cost of one order of chicks from the hatchery, you can get a trio ( or maybe a pair) of exceptionally nice birds. Maybe not the Grand Champion, but birds that give you the possibility of raising a Grand Champion. You just have to start with fewer birds. But with an animal that can lay 300 eggs in a year, it is very fast to build up a flock.