Do I have to use the plugins as described in your sales page?
No, you don't. When using Listify you can use it without any of the paid plugins for a directory that allows people to post listings for free, and when you want to start charging listing owners to list a on your site you will need a plugin called Listing Payments the cost of that plugin is 29 dollars. So far you have spent 90 dollars for a site that allows you to make money from listing owners, that's great value!
Now let's say you want to charge a subscription to the listing owners we recommend using the WooCommerce Subscriptions plugin, which is 199 dollars, which we think is fair when you are collecting money from listing owners weekly/monthly/yearly, so now the cost of your website is around 269 dollars which is really not that expensive when you are collecting money from listing owners on a recurring basis.
Now let's say you want to add Social Login on your site, you can use the official WooCommerce plugin.
If you want listing owners to be able to display a booking system alongside their listings then there are many different ways to do that, either with OpenTable, Resurva, Guestful, or with the WooCommerce Booking plugin. Keep in mind if you don't need a booking system on your site then you don't need the plugin or to use the third party services.
If you research WooCommerce plugins you will see there are many free and low-cost alternatives. We simply recommend the official plugins as being completely compatible.