I am supremely confident that you will not get a direct answer to this question from a qualified Microsoft employee, who is able to define, say “too expensive.”

When I am permitted to speculate, I would say that Microsoft defines a small business as one that makes just over a million U.S. dollars a year. You and I might define a small business as one that makes over $50,000 and under $100,000.

Our small businesses would definitely welcome SQL Server Express over MSDE and Access!