Question about NBA jerseys?

I want to buy NBA jerseys i looked them up and theres Replicas, Swingman, and Authentic. what is the difference between the three other then the replica is the cheapest? what makes it cheap?. Ill probably use these jerseys when i play ball so which would feel the most comfortable while playing? Also are the sizes different? like would a Large swingman feel smaller or bigger than a Large Replica?.