Azure Traffic Manager Nested Profiles support is generally available with no additional charge.
Traffic Manager Nested Profiles enable you to create more flexible and powerful load balancing and failover schemes to support the needs of larger, more complex deployments. It does this by enabling you to combine different load-balancing methods, such as performance load balancing to route to the nearest Azure region and weighted load balancing within that region to distribute one percent of your traffic to a new deployment as part of a test in production rollout strategy.
There are many other ways you can combine profiles by using nesting. A variety of examples are given in
this blog post, which describes the feature in full.