I want to determine market demand for a product I am developing

My goal is to test the market demand for a new web-based service I am developing. In order to determine potential sales, I plan to use online advertisements (Google Ads, etc) to gather buying interest from potential customers. It's important for me to know how many people click my buy-now buttons. I'll be most interested in Conversion rate on my landing page's buy buttons. My Google Ads accounts have been suspended so I can't test this myself (plus I'm not very good at running ads anyway).