No idea what your marketing budget should be? Because marketing needs and costs vary widely, there are no simple rules for determining what you marketing budget should be. A popular method with small business owners is to allocate a small percentage of gross sales for the most recent year. This usually amounts to about 2% for an existing business. However, if you are planning on launching a new product/service or business, you may want to increase your marketing budget figure, to as much as 10 percent of your expected gross sales.