They cost of a youth competitior and an adult is completely different, the two are just are not comparable.
We compete both independent competitions and chain comps,(for us FADS) as AM/AM.
To a large extent the cost of a competition is within your control. Even at a chain studio, the instructor can only dictate the amount of entries that you will do if you allow it. For example next month we will compete FADS with 12 entries(one being a five dance open champ)We always tell our instructor what we will do, not visa versa. For us the attraction is the comp, not the extras. We do not buy any of the meals, shows, ect... Just entry/entrance fees and a one night hotel... Thus, you can control the cost. You should/must ask the studio to give you a break down of the costs so you can make an educated decision. DO NOT go into this blind or yes it will easily cost you $3,000.
On the other hand, if you have never been to a comp before I would absolutely suggest you purchase the shows just to experience what it is like to go to a pro show..., expereince the entire atmosphere. You can also do just a few entires to see if it is for you. The experience will be the same, just less entries.
In the end we all make our own decisions as to how we want to spend our dance dollars. For us, we compete often without a lot of entries, the idea for us is quality over quanity. A good deal of our $$'s are spent on priviate lessons to prepare for comps and less on the frills of a comp.