OK, i read all of this post and as a new Ball hobbist i got my thoughts on this for you.
I think starting anything at a young age is really good. Most people get started later in life and get old before they can enjoy a lot of what their goals were. So that's a BIG plus for you.
I would think any 15 year old with $20,000 available would not be needing cash flow(or a little extra money). I also think with that money and a job and a good Mutual Fund, you could be doing very well by time you 20 or 22.
OK, but if you really want to get into Balls, you got to kinda come into it liking them for what they are and not a money maker. Remember, its a lot of work and disappointment. You see all these breeders selling Balls left and right for lots of money. But the reality of a lot of what you see is not that at all. Lots of Balls sit around and get re-listed over and over. Lots never sell period. Look at Pastels now, seems like they are coming to a stand still. Males can't move for $1,000. So you breed a male Pastel to 3 females and lets say you get 3 or 4 males out of it. Then you can't sell them, what do you do? They still have to eat, they still have to be cleaned. Thats money down the drain as a business investment. Then what if the following year you put what you have together and get 4 or 5 more males, now you got 7 or 8 male Pastels that eat, need cleaning and you are stuck with them. That will make you wish you never went this route as an investment. That's why i say you got to LOVE doing this not wanting to make money from it.
Remember, if you love doing something, do it well, money will follow...
Ok, $20,000... If you just had to do this and will not take "no" as an answer. This is what i would do. 1st, want to start with racks(HOUSING), need a home before getting the Ball(s). So if you can get wood and all(cheap) build your own. Most people(posts) i see say they build racks that hold like 4 to 6 Balls for under $150 all included(tubs, water dishes, heat, controls, etc...). So if you plan on having 20 Balls as a breeding project, build housing to hold say 18 Balls(3 racks) to start with. Then build a rack that is for babies(holds say 20 tubs). So thats 4 racks that will cost say $700(give or take).
FOOD is next, i would go with breeding them(mice). If your looking for investment, its the cheap way. Then buy froozen rats. This way you have a cheap supply of food. I have 4 colonies of mice and they produce about 160-180 adult mice a month for me. Bedding and food only costs me about $10 a month to keep them. So you get 160 mice(food for Balls) a month for about $10. Then but your froozen rats in bulk and get them somewhat cheap too. I do not feed mine many rats and they grow like weeds. So i do not think you "got to buy rats" to do well.
ODDS & ENDS, you will need money on the side for all that. Electricity and so on. You can more than likely get away with $1 a day to heat them. Vet bills, well, have a little set aside(maybe $50 a Ball as insurance) per year. Put in interest account(if money is not used, its making you money)(never let unused money sit).
OK, to the BALLS themselves. If your going Pastel, that's fine. I would not go with a small male and 3 small females(like someone said). If you got $20,000 and can use it. Why wait 2 to 3 years to see a return? I would buy a breeder sized male and 3 breeder (ready) females. Yes, if you go with 2003 Balls you will get away with $1,300(like someone said), but why? Take $3,500-$4,500 and get adults. Then you can breed this season and get a return a lot sooner. In the long run, your money will work for you longer, thus giving you a bigger return. And remember, one big reason people get out of a investment is because returns take tooooooooo long to see(get). Also, i would even invest in Albino's(kinda the bread and butter) of breeding. Get adult male and female(maybe $6,000) and see results this season. And maybe you could get a deal doing the whole shooting match with one breeder(buying) or maybe with the Albino's(1.1, get a 100% het female for $500). So yopu have 2 females to breed, the Albino and the het.
So, for say $11,000 to $12,000 you could be well on your way with returns on your investment in less than 8 months. But then what do i know, been doing this for only 11 months...
PS- I am sure someone or a few long time breeders will blow my plan out the water. I am sure it has flaws. But its at least a starting point and maybe others can add to make the plan better. Thanks for the question...
JAZ