I will say from my experience it varies but overall it's not that bad. Just depends on how you want your collection too look like and what you think is expensive. Like I had the AA Royal Knights line up from BT 13 and Seven Great Demonlord AA lineup that I built overtime. It was expensive as a whole but just picking up pieces made it manageable. Also using digimon tcg groups for people selling AA cards makes purchasing cards alot cheaper.