This is a question only you can answer. Sites are billed based on the resources they consume (bandwidth, storage, and CPU/RAM). The cost is therefore based on the size and popularity of your site, as well as any optional features of our service that it uses (like domain registration or MySQL).
We don't know any of those things about your site, and we are not able to estimate things about your site that you don't know yourself. If you have your own estimates or past records about your site's size and popularity, you can use those, plus the pricing information available on our site, to estimate the approximate cost.
We do provide a Pricing Estimator you can use to try to get an idea of how much your hosting may cost.