Leadpages is a top landing page builder connecting multiple domains to one builder account. With a Leadpages Advanced account, you can connect up to 50 custom domains to one website. Each of those domains can have up to 20 subdomains attached.  Landerlab also lets you add multiple domains to one account. Right now, there is no explicitly stated limit on their website. So if you’re looking for affordability, go with Landerlab.