Im with @weinoo
if you are lucky to have a convenient place for chicken carcass , and it fresh and inexpensive
go for it.
of get a whole chicken or two on sale , use the breast and thighs , and the rest for stock
hopeully via an iPot , and it makes the process simply mindless
I sont know what chicken costs at Costco , or BJ's
but it routinely sells on sale for $ 0.79 whole , legs , thighs etc
can't say which parts if they are all at the same price is cheapest for yield ( best flavor ) in making stock