The cost to develop a marketplace depends on the option you choose. There are essentially two options for developing such a project.
1. Existing Solutions: You can develop on a platform, that offers certain ready features. Using these platforms is the fastest and cheapest way to develop such a website. These solutions start from a few hundred dollars, depending upon features, and cost increases with more features.

2. Build from Strach: Although this option demands more on time and money, a bespoke marketplace can be customized to meet your specific needs better than a platform. For functionality that is deeper and more robust, you may need to custom code a greater scope of features. This kind of online marketplace can be $20k or more.

Corresponding, maintenance is approximate $1,000-$1,200/year and will be focused on adjustments to the functionality.

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