Sorry but the terms "best & cheapest" are in total conflcit with each other and do not go hand in hand. You get what you are willing to pay for.
A better way to look at this project total value - warranty coverages, reputations of the supplier, local installer response time when you have a critical need, local inventory on the shelve options that may fit you operations better to give you long life, improve safety, etc. etc. etc

Start by making a spread sheet and make teh decision from there