To help with the funding for start up costs and such, why not advertise first? Invite some airsofters down to help you plan the layout of the site; where cover needs putting, what to use to make it - stuff like that.
Once a few people have seen it, you can offer them a free game or something similar...
IF they can bring 5 paying players to the first event. Also, running the event for about £15 will attract more people, you could say you were giving them a discount for the first trip, for being the first to play on the site, usual price £25, first time price, £15.
£25 is a bit steep for a brand new site, people don't know what they're getting so they might just wait it out to hear the news.
£15 is cheap enough to draw people in, but expensive enough for them to not think, "Oh that's cheap, it must be crap and under developed with nothing there at all if it's only a fiver" plus, if you call it a discount, it seems like a deal, so people will want to take advantage of it.
You could also offer membership for free to the people who come to the first 3 games, then after that, once you've got a member base, charge £25 for the year, to knock £5 off each visit, making it £20 instead of £25 for members.
That way, you could make a lot of money fast, the first wave of money will be people drawn in by the discount, then you'll get the next wave from people returning because they have free membership, then the 3rd wave will be from people signing up to become new members, because they've heard so much about the site, from the cheap prices, the fact you have a member base already and that you let airsofters help you set it up how they wanted it.
Simples.
35% cut please
Haha.