I'm sure that the RStudio staff can jump in here and avise you on the specifics on Shiny plans, but if your app's computation involves simply filtering a data frame and rerendering an associated plot, you might also want to look into crosstalk. It allows one or more plots and some simple controls to talk to each other in some limited ways (including filtering and brushing), and the set of plots/controls can be rendered out as a static HTML file (essentially in the same way any other htmlwidget would be rendered).
This HTML file can then be put on a host for static sites, like GitHub Pages or Netlify, and take as much traffic as you want, which makes it great if you need to handle a surge of initial traffic rather than regular, ongoing traffic 