By onesy-twosey questions, I mean asking a question, waiting for a response, asking another question... by the time you have asked all the questions you need to, the fish will be too old to breed.
You are on the right track with the equipment list, but it's better to have a couple of large air pumps and an air manifold, that way you can drop 3, 4, or 5 airstones in a tank. You will need that much air; bbay fish suck up oxygen fast. More on equipment later.
It's hard to say how much a pair of fish will cost. Two fish that you pair up will be cheap at $10-$15 each. You will wait 1, 2 or more years to get them conditioned and get a first spawn out of them, and then they need some time to practice and get more mature, so you will probably not get healthy nests for at least several months after that.
"Pairs" are for sale on this forum all the time. They are two clowns that live together and have a pair bond, but have never spawned. Depending on the age, you may be able to condition and deworm them and get a first spawn within 6 months. If they are mature, say 3+ years old, they may begin producing healthy nests fairly quickly.
"Spawning pairs" are pairs of fish that are proven spawners and are producing nests regularly. These fish, depending on markings, etc., can go for $100+ per pair. $300 for a nice pair is not unusual, and I have been privately offered much more than that for my gobies. Moving the fish to a new tank will often result in them stopping spawning for months; some resume in a month or two, some may get moved and never spawn again or worst case scenario, the pair bond breaks.
Ocellaris are gentle and not as easily disturbed. They are unlikely to break their pair bond unless handled very badly and will tolerate conditions other clowns would mutiny over. They are also fairly cheap to acquire and hardy, and there is always a market for ocellaris babies.
A single broodstock pair can produce quite a lot of fish and wil be plenty to get you started. Once spawning, they spawn every two weeks and you potentially end up with 25-75 fish per spawn that reach saleable age and did not have to be culled. Sounds like a lot of fish, right? It's not much for a fish store. You might keep one small fish store in clowns if you raised every nest they produced. Fish stores are unlikely to give good prices (or even to buy at all) from a very small supplier because it will be too much trouble for them to deal with, and they will think of it as doing you a favor instead of the other way around.
Each nest will need at least one 10g tank (start with 5g of water and move up as they grow), receiving 50% water changes with aged mixed SW daily. Once they are in growout, a 10g-15g tank will be fine for each nest, but you want them to live on a shared system with a sump and skimmer, UV, etc.
That's not counting 2-3x the volume or larvae tanks with heavy rot cultures for the first week of feeding (which you will need to keep going constantly to raise every spawn), 2-3x the volume of rotifer tanks for growing phyto (can be replaced with frozen algae paste, but that's much more expensive), and brine shrimp hatcheries for BBS for the next few days after that... plus enrichment diet, different graded sizes of baby fish food, Clor-Am-X water conditioner, etc. And did I mention salt mix by the pallet?
Raising that many fish requires a garage full of stuff. Anything less than that many babies is not really financially feasible.
Now, if you want to do it for fun and just raise a few batches to sell to other hobbiests, you can scale down to several tanks and buckets of cultures. (Like what I did.) You will not make money on the project, but if you are careful and very lucky, you might break even after 6 or 7 good batches of fish; maybe sooner if you have a good pair laying big nests and you have a blue thumb so you get lots of babies to saleable size.
On the downside, it almost as much work to raise one batch of fish as it is to take care of 10 batches.
I suggest you hang out in the breeding forum and do some reading there, not just the technical details but the complaining and venting and posts full of frustrations. You will get a better idea of the work involved and the complexity of some of it.
Raising clowns is not hard, really, but it requires lots of diligence, time and attention to detail. The ONE day you get lazy and decide to do that water change in the morning because you are tired can mean a tank full of dead clowns.
Good luck!
