I disagree with this popular notion. A website should be a fully functioning sales system, so that it helps ease the admin burden of a small business, and also helps them get more sales.
Take the most common small businesses: Restaurants and accommodation. Both of these can save/make thousands of dollars per year by having their own ordering systems on their websites.
As for the other small business which perform more bespoke services, it's good to have offerings for set prices on the website, just so that customers know what they can expect when contacting for a bespoke solution.