Can 偷工减料 be used to describe the intentional and open purchasing of somewhat inferior product?
偷工减料 means shoddy/poor workmanship and lousy/substandard materials. It is not something you would use to describe intentionally buying something that is inferior or less expensive. It is by nature something that is deceptive or dishonest or even corrupt and dangerous. It is more severe than cutting corners, which is sometimes associated with the term "cost down" if cost reduction is being done dishonestly.