You will need at least a single standard Streaming Endpoint. If you have a lot of traffic, greater than 600Mbps egress, then you would want to upgrade to more than one Premium Streaming endpoints to scale. But for starters, just calculate a single one, and monitor the metrics for CPU and egress on it to see how you are doing at first with the CDN enabled on it.
All egress from the Streaming Endpoint is metered with the CDN egress meters when enabled. Otherwise, it would use standard data egress rates for your region/zone.
For encoding, the pricing is pretty straightforward. There are examples in the FAQ of the pricing page.
That's about it, other than storage costs...but that is also fairly easy for you to calculate once you know which encoding profiles you are using and you know the amount of source file sizes you need to store and for how long.
Hope that helps!