Lord Nagafen Raider
The large ones are just under 800 million in Jita , Small oens are made from Large Injector's so of course are slighly less, not sure where you got your billion cost from.*edit - looks like Jita is just over a 1B for one. Damn.
Best place to find costs are here - EVEMarketer - eve-central is not missed because this is better [nicer layout too].
They have done it with titans for their alts before.You can go from new character to carrier pilot with enough injectors in 10 minutes lol. Not saying it's a great idea, but I'm sure someone has done it.
In inter-galactic news Razor Alliance have lost two keepstars in a day, thats around 600 billion right there and thats discounting the rest they lost yesterday.