If you're running ads, then an ad should work very quickly. As Artashes said, it's going to depend who you're targeting and what you're saying in your ad to convince the user that you're the host to go with.
Keep in mind, if you're targeting savvy users, they're going to go look at places for hosting reviews etc, so definitely do not target generic terms like "shared hosting".
What you'll want to check up on is how many people are seeing your ad, and how many of those people are clicking to go to your site. Getting 1,000 views on an ad doesn't mean anything if nobody is clicking the ad.
Targeting a niche, is going to be a heavy requirement when starting out. Then making the signup process as easy as possible and evaluating the Goal path of a user to see where they fall off is going to be something to review too.
To make things cheaper on your end, you'll want to take advantage of the Facebook Pixel and Google Pixel and retarget users based on if they visited your site. You can also setup "look-alike" type marketing where the ads are setup so that if a user looks as "godaddy" for example, then your ad should show to that person. (DO NOT use the entire site of godaddy as a look-alike target, you would want to target specific pages in their site, and then have your ads show - for example, targeting the "cancellation policy" or specific "user help" sections of their site might be a good target)
There's a lot to the marketing end of things. A pretty site and competitive pricing is only half the battle. You'll want to build a persona of who it is you're trying to target, then as Artashes said, build a specific landing page dealing directly with that issue.