I use Gravity forms for a For Sale Page to sell horses. We want our customers to be able to login like a membership to pay and add their horses to our site, once we approve them. Is that feature available? If not any suggestions.
Gravity forms has a user registration add on available with their elite package.
You can also hide or show forms based on whether the user is logged in.
However, this isn’t a full blown membership plugin.
You may want to look into
They have a manual member approval function, and you can prevent non registered users from accessing specific pages, such as your horse checkout pages.
Gravity forms also can let you create new post from form submissions. So that people can add horses.
Other than Gravity Forms for creating post, Gravity view is an excellent alternative and is an approved third party developer.
There are several ways you can go about configuring this functionality for your website. Hopefully this will help give you some more direction.