Commercial areas in a city can take up about 5% of a city’s land. It is used for commercial activities. These activities include the buying and selling of goods and services in retail businesses, wholesale buying and selling, financial establishments, and wide variety of services that are broadly classified as "business". Even though these commercial activities use only a small amount of land, they are extremely important to a community’s economy. They provide jobs and bring money into the community. A commercial area is real estate intended for use by for-profit businesses, such as office complexes, shopping malls, service stations and restaurants. It may be purchased outright by a developer for future projects or leased through a real estate broker. This type of property falls somewhere between residential and industrial property. Practically every incomer must grant permission to build a new office complex or other profit-making business, the city government must determine that the chosen area is indeed commercial area. The zones which separate commercial, industrial, and residential area are clearly markeoned for commercial use, then the city will allow the sale to proceed for the stated use. If any part of the property extends into a residential or industrial zone, however, then the buyer must seek a 'variance', special permission to cross over a zone boundary A commercial area can be held by real estate agents who treat it the same as residential areas. Signs advertising the availability and size of the real estate can be erected, and arrangements can be made to buy or lease smaller lots. Sellers may also agree to make improvements to the land, such as grading off uneven spots or clearing out unwanted trees. A professional developer may purchase huge swatches of this type of property simply to guarantee its availability for later projects.