I cannot tell how old this question is, so my guess is that you have begun your build. Judging from the context of this question, it sounds like money is or was a concern. So, here is what I would do:

You mentioned AirBnB. There is a wordpress theme built to function almost exactly as AirBnB. I am currently using this theme as a directory site and it's wonderful: https://templatic.com/app-themes/spotfinder-responsive-directory-theme
If you mentioned AirBnB because it is the closest to what you'd like to create, then I'd strongly suggest starting with that^.
If you do, have a VA begin to put together .csv files using their bulk-uploader template found in the plugin:
https://templatic.com/wordpress-plugins/bulk-import-export-wordpress-plugin
This will allow you to get thousands of listings added to your directory in a matter of days.
Total cost for the theme, the install, customization and VA's time: < $500

(For a platform similar to Clarity, I don't believe there is a wordpress replica (yet). They used custom bootstrap, so check out CMS themes available here; https://wrapbootstrap.com/)

So you're off and running. Now you have your MVP platform to start selling, and bots starting to index your pages (speed this process up by submitting your URLs under Google's search console).

The important thing to realize here is that this is not your end-all-be-all. This allows you to get up and running, work out your sales process, find your early adopters and build up your search rankings.

The next step, as soon as you've proved your marketplace idea is competitive and/or in demand (from both user types), is to begin your custom build. For this, I still recommend going with a slightly out-of-box solution. Check out these two options:
Sharetribe.com (for more ecommerce buying/selling platforms)
Growthclick.com (for more service-based business platforms)
Both options will give you a stable and scalable code-base to work off of - and you can either license the code for one purpose, or buy it out completely. Sharetribe also has an open sourced code you can use if you are confident in your dev team.
Total cost for this option will either run you $10K-$50K, or $2-$500/month.

The point I'm trying to make with all of this is that, especially with online marketplaces, there are tested/proven options available you can and should consider before beginning an custom build.

In any case, your first platform is going to be your "beta." Whether you hire someone and paid thousands to build it from scratch, gave away a ton of equity and waited months for your new partner/CTO to build it him/herself, or decided on an out-of-box solution like the fore mentioned, you are still in the proof of concept phase. You haven't proven out your idea, team and business model.

Common [expensive] realizations that happen during this phase include:

1. "Why did we decide to launch with an iOS app when a mobile-friendly web-app would have been plenty?"
2. "We brought on a CTO who we thought could get us through proof of concept, but all they did was build us a working database with an ugly front-end. Now we need to pay to build what users want today - a secure, well-design, mobile-friendly platform, but we're out of money."
3. "Conversion to signup and/or order rates are low, but our dev bandwidth is all focused on building our flashy new mobile app, so we can't make the front-end changes we need to convert traffic."
4. "User attrition rates are high, but we blew through our budget getting through our big post-launch push, so we cant afford to make the changes we need to retain users."
5. And, "We found the brand new _____ platform that has the exact same value proposition as we do, but has already reached a substantial user-base and has been mentioned in the press."

My point is, right now you should be focusing time/costs/bandwidth on user acquisition and pushing as many transactions as possible through your beta. Get what you "need to have," not what you "want to have."

For more on this, check out: http://chickenandegg.io/faq/