Google is a Search Engine and SEO is about optimising your spot in the Search Engine. It’s all about being on page 1 and as close to the top as you can get.
Yes, having a standalone website with no SEO will be cheaper but it won’t help get you business. If set up with the right company, they will not only get your site to rank well in Google but also help generate qualified leads to your business that will pay for your online presence and help make your business money.
A stand alone website without SEO is pointless you need to make sure your website comes up when people search keywords in Google that are relevant for your business.