You can keep track of cost at the very first stages - while designing your stack
At the bottom of the property panel located to the right of the IDE you will find an interactive cost estimation detialing the rescources you are using and the cost they are likely to incurr
At the validation stage VisualOps offers you an estimation of the monthly cost to run your app.
This is prior to any cost being incurred so you are able to go back and scale your app up or down to stay in keeping with your budget. If you're happy with the estimation click "run stack" to launch your application