What you are proposing is extremely difficult. You want to vault year round. Obviously you need to be indoors. Finding a facility large enough to fit athletes of elite caliber is tough. If you do find it, you have rent or mortgage which varies greatly, plus healthy utilities that can be upwards of $1,500 to $3,000 a month especially in the winter. Then you have the cost of equipment. Pits, runway, box, poles. Thats an easy $20,000 to $30,000 right there. Its a lot to take on.
If your serious about it. Here are some ways to try and cut corners. Don't try to make the biggest fanciest facility in the US and then wind up losing it all or never making it happen. Start small, build up clients and possible investors. Then you can think about nicer pits, more poles, better location, ect.
Here's what you do
1. Find a pit
Colleges and highschools are always replacing there old pits. Find an old one, spend a few hundred bucks on new material and foam if necessary. Make it safe not pretty.
2. Find a building.
Get in close with a Gymnastics gym, indoor soccer/lacrosse/hockey or even skate park. Figure out some kind of common ground on rent, then go for it.
Try to sink a box if you can, tell them that they can always just fill the hole in if it doesn't work out. This is the cheapest way. Otherwise your looking at building or buying a raised runway. This is more than likely the case. People generally don't want holes in there floor. Even the cheapest ways to build those aren't cheap. Try and find someone who works at a lumber place and work a deal with them.
Go to highschools, colleges, polevaultpower, craiglist, ebay and get some random cheap poles. You can also become an exclusive dealer for one of the main companies and that can be another source of income for your club, and you will have access to much cheaper poles. Another way is take a college or highschool coaching position, then you have access to there poles. In the off season you keep them in your building, during the season you transfer them back and forth. This tends to be more realistic.
easy ways to get the word out are Fliers to every area highschool, I'm talking at least a thousand fliers. Make a flier with dates, times, location, and make it appealing. Send them out to Highschool AD's and they will get the word out for you. Facebook, start a page for your club and constantly update it. PV Power, make sure to get it on there and keep having events that update it as well. A website is always good as well, but an unnecessary start up cost now that social networks make it so easy. You have to have programs for all ages, or you won't make enough money to stay afloat. Investors always come and go, most never stick around for more than 4 years.
Good luck. PM me for more questions, i've been part of several of these in different states, and have a pretty good knowledge of how to keep them afloat.
If someone tries to step on your dreams.... Step on their face.