SBA Recommendation on Marketing & Advertising
As a general rule, small businesses with revenues less than $5 million should allocate 7-8 percent of their revenues to marketing. This budget should be split between 1) brand development costs (which includes all the channels you use to promote your brand such as your website, blogs, sales collateral, etc.), and 2) the costs of promoting your business (campaigns, advertising, events, etc.).
This percentage also assumes you have margins in the range of 10-12 percent (after you’ve covered your other expenses, including marketing).
Gathered from the Small Business Association.
Whether a total budget is set in a retainer or the budget is pay as you go, 10% of the total spend is my fee.