Outdoor signs are either lighted or unlit. A lighted sign generally has an internal illumination source such as LED, fluorescent, or neon. Unlit exterior signs do not have an illumination component. However, it is possible to use external lighting sources to illuminate an unlit sign.
Another distinction among building signs is individual or integrated elements - letters and logos. Each letter and logo of the sign can be individually manufactured. Alternatively, a self-contained sign can be produced that combines the letters and other elements in a common cabinet.
Sign prices are determined by overall size of the sign, number of elements used in the sign, and whether or not it is illuminated. Most lighted storefront signs will cost between $3,500 and $5,500 each. Unlit signs are generally about half the price or between $1,500 and $3,000 each.
Size is a function of the message you want to display and the distance over which it needs to be legible. Shorter messages to be read up close are less expensive than long messages sized to be read from the roadway.
The next component that determines sign price is the number of elements in the sign. Elements including the number of letters required to deliver your message and the logo and supplemental messages that make up the sign (listed services, tagline, etc).
You may need approval from the property owner as well as the city. Commercial property owners often specify the type, size, and even colors that are allowed for their tenant's storefront signs. Once the property owner approves the sign, then a sign permit must be obtained from the city. City ordinance generally specifies the type, size, and number of signs that are allowed within the zoning area where you are located.
Generally you need to plan on a total 4-8 weeks for your custom sign. Approvals can take 10 business days or more. Once approvals are obtained, then production can begin. It generally takes between 10 and 15 business days to manufacture the sign and get it installed.
A sign made with quality components will last 5-6 years without major repair or maintenance. However, quality components are key to answering this question. Signs are constructed from metal, vinyl graphics, acrylic, lighting modules, and power supplies. Various quality grades are available for each of these components. Cheaper components are always available but quality components will ensure that you have a custom sign that will look good for years and require little to no maintenance.
Be sure to work with a reputable sign company that has experience with the type of sign you need. Discuss their choice of components and rationale for why they use those components.