100% build your own. Will be a fraction of the price and your chickens will likely do much better in them. Beyond that, price can be driven down even further by using second hand materials.
As a general rule, set up your plan to include:
4 sq feet of coop per chicken
1 foot of roostbar per...
After getting into chicken raising, I still can't get over how comically cheap the chicken itself is compared to everything else that goes into their care. In total, I've put like $40 into live chicks, but well over $1000 between food, shelter and other incidentals. Not even including the blood...