Outposts are stations in sovereignty null sec, which players constructed, and which behave just like NPC stations for now. They cannot be destroyed and your items remain safely in them if you lose access to them should they change ownership. However, they will be turned into Structures in a few weeks, and then assets in them will be treated differently.
Structures, or Upwell Structures (citadels, engineering complexes, refineries, and whatnot else CCP will introduce next) can be destroyed and your assets’ safety within these structures depends on where these structures are.
If the structures are located in High sec, Low sec or Null sec, your assets will be locked into Asset Safety and transferred to the nearest high sec station or low sec station.
If the structures are located in Wormhole space, your assets will not go into Asset Safety and instead drop as loot for everyone to take.
You can only build structures, which you can just buy on the market. Building actual stations or outposts is not possible.
If the structure is destroyed and your items end up in asset safety, you will need to pay 15% of their value to retrieve them again.
If your assets are inside a POS module (old-type player owned structure, currently being slowly phased out) or a mobile depot when it gets blown up, your items will drop as loot.
As for getting your own structure, you can deploy anything from a small mobile depot (useful for refitting and storage when away from home) to a large citadel. Also the old POS can still be deployed. You buy the item on the market, then you have to anchor it and in some cases add fuel if you want to online modules to provide services. Be ready to defend your new structure from griefers, pirates, and general PVP types if necessary.
Initial setup costs for an Upwell structure would be a billion+ (at minimum - add more billions if you wish to make it actually do something useful) and the fuel costs will run you anywhere from a hundred million to a billion+ ISK per month, depending on the type and amount of modules that you bring online. That’s the cheap part though, the more expensive part of the equation is keeping the structure safe. However, plenty of “one-man” corporations do in fact own such structures (and plenty regularly lose them, too).
I just saved some stuff and a Myrmidon from a destroyed Fortizar in Highsec and had to pay 343k ISK - that’s hardly 15% of a Myrmidon!? So 15% only for Items, but not for ships and their cargo?
Deliveries to an NPC station (Edit: or to a citadel/Upwell structure, as pointed out by another poster below) in the same system currently only charge 0.5% of the value - if you act on it fast enough (you have 20 days I think). That would value your Myrmidon (+stuff) at 68.6 million. Probably not far off.
I actually thought they changed it from 0.5% to 15%. But apparently it was free in-system before and was changed to 0.5% recently instead. Apologies for the confusion
It should still be 15% if delivered to another system or if you fail to react in time.
Deliveries to any station or citadel in the same system only charge 0.5% within the time period. I transferred stuff from one citadel to another when the first one got blown up for only 0.5%.