If you don't have a discretionary spending limit that will accommodate it, then trying to get OSS through procurement is difficult. Who is providing the support contract? What level of indemnity insurance is the supplier covered by? Can you get a spread of three quotes from competitive providers?

Not to mention that if the supplier isn't VAT/GST registered, the accounts department can be operationally incapable of accepting an invoice or issuing payment.

Not malicious, this is best practice for a large organisation that needs to prove that it is not doing fraud. But it does present a huge obstacle to buying from small organisations, startups, and one-person OSS maintainers.