Thanks for the helpful comments.

Meesa,
You will pay an entry fee for each single-dance heat you do - somewhere between $25 - $35 per heat. Multi-dance heats such as championships and scholarships can range from $50 to $100 to enter. You will also need to buy your own admission ticket to the ballroom for each session you attend. Those costs are what the organizer charges. You usually can buy these either a la carte, or organizers very often put together packages that include meals, hotels and other things, depending on the competition.

As for what the pro charges on top of that: I've competed with a variety of pros, both chain and independent, and each one has a different fee structure:
-One charges a flat rate of $200 "per day" no matter how many heats I enter. So, if I'm there 2 days it's $400. He won't go to a competition unless there are at least 3 students going.
-One charges a "per competition" fee of $250 plus $10 per dance (so, if I've entered a 5-dance heat, that counts as five dances) Also, if I'm the only student going, his "per comp" fee increases to $300.
-One charges $25 "per dance." Again, if I'm in a five-dance heat, that counts as five dances.

On top of the pro fees, you will also expect to pay a share of your pros admission tickets, travel costs, and hotel that will be split among the number of students attending.

It does mean that you have to assemble the various pricing components and do a bit of math to see what you would pay for the number of entries you want to do, and whether a package is a better deal than a la carte.
If you don't want to do the math yourself, well, Chain studios usually will give you a single "all included" dollar amount to attend a competition that lumps together hotel, meals, entries, admissions, pro fees - but they quite often are very, very, very reluctant to break out the costs for you. Some people don't mind that; others do.

Speak directly with your pro. He/She should already, if they've competed before, know what you will pay on their behalf. Also, if your competition is not associated with a chain studio and is advertised on the web - you can get a pretty good idea as the other costs. Many competition will package all the costs together into a variety of packages. For me, I pay the entry fee for each dance, average cost $35, my pro charges a per entry fee so add that to the entry fee cost, then you will have to pay for his/her admission ticket for the session your dancing in, is there a hotel stay involved? I have paid for his/her room and my own room, any air fare. It always helps to have others competing with your teacher as thir reduces the cost of the pro since it will be split among the students. If your dancing in a chain competition the studio will already have a set price the you will pay - unless your teacher is an independent teacher. Some teachers will simply charge a flat rate rather than the costs I've experienced above. Other dancers I know stay close to home so they do not incur a hotel stay, travel - etc., which reduces their own cost as well. Sit down with your teacher and have this discussion - so your not feeling surprised later on down the road. (-:

My pro charges a flat fee (several thousand $$) and I pay all f his expenses. Those are split amoung each of the students going.
Please talk with your pro and discuss your goals. This is his profession and he will help you come up with a plan.

Pro/Am competitions are very expensive.For instance if you take your professinal away from their teaching for lets say even only three days. In their studio they would be teaching something like six hours a day at say $60 an hour. Add to that the other expences involved, travell , food, accomadation plus the cost of entering the comp in the first place. Add your own expences to that, it is becoming a rich persons sport.

I agree with Cyd.
I have students who have to pay for the time that I am there and not teaching.
I dont do a per dance entry it is a flat fee.
But yes it always has been and alsways will be (in the usa) a rich persons sport/hobby.
With that comes the snobby nose in the air attitude of so many students out there, because they have money and take coaching lessons with 'celebrity instructors' they think thay are better without really knowing much more.
But thats a different topic.