Hi, I've got a considerable amount of experience in assisting my clients with understanding what they are up against for many kinds of projects, so let me clarify the "It Depends" answer with some rough estimate $ Figures.

For a Wordpress experience where you take an exiting Wordpress website template, and add a plugIn with no customizations, and you use a well experienced consultant for an hourly rate, you can reasonable expect a $5k to $10k cost. Installation is fast and easy. Most of this cost will be for content setup. Corresponding maintenance is approximately $250-$1,000/year and will be focused on keeping plugins up to date and may include keeping you content up to date.

For a low scope of work effort, where features are few, functionality is easy and where custom coding is added to an existing website, and some content loading is needed, you can expect a $10k-15K cost. Most of this cost will be for coding and testing. Corresponding maintenance is approximately $1,000-$1,500/year and will be focused on adjustments to the functionality.

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. The greater your functionality needed, the higher the price will go. I cannot give you an upper limit here because the possible features are many. 70% of your cost will be for coding and testing. Corresponding maintenance is 5%-10% of your build price per year and will be focused on adjustments to the functionality.

A word of caution. Many websites promote low cost. This doesn't mean you will get the features you want or give your website users a friendly experience. This kind of low cost choice is a trap. If your website is intended to be your primary means of promoting your business, and generating revenue, you should pay a qualified professional to set it up in quality fashion, with the features you need and leave your users with a pleasant image of your company. That comes with a cost.

Good Luck!