Knowing your ideal market and price point are important in all types of sales. Knowing where to invest your effort to reach your most likely consumer is an important part of integrated marketing. There are several resources available to document income levels, hobbies, political affiliations, and other consumer spending information.
Most recent census information is one way to zoom into specific areas and see average income levels.
Of course, income level is only one of many infobits that you should use to hone in on your clients, but it can be very useful, especially for organizations that are fundraising.
Visit http://www.richblockspoorblocks.com/ to find more information and maps on income levels in every neighborhood of the USA.
Not everyone is your customer. Invest in information to better focus your efforts to reach your customer.