Your website needs to be mobile to be found in Google Search, so as much as you may want to have an App, you need a mobile site! Yes you can use an app as your mobile site, but that will not get you into Google mobile search.
Mobile search makes up 50%-75% of all search today, so besides being mobile to be included in all the organic search, you may also want an App to capture and interact with your customers and potential customers.
The short answer: You have to have a mobile site, you really should have an App for your business if you have repeat customers (or you want them!)
Basic apps start at $599
Hosting on Apple/Google Play is $30/month
Can you afford not to adopt the newest technology
Get into their phones and you are in their pocket!
Reach your clients 24/7 via text messages!