An important thing to consider when selling to BFE's is not just that their budgets are larger, but the value they will receive from your offering is bigger, too. I see a lot of SaaS founders get embarrassed about charging enterprise rates, when, as Patrick says, the rates don't even really matter at that scale. Yet while they may be able to charge 20x as much as their regular plans, they may be delivering 50x the value. Make sure you have a good understanding of how your application will provide value, and how they will measure that, not only to support your sales efforts with the customer, but so that you feel confident about your side of the sale, including the price.