Thanks for stepping up to the plate, Zetetic. I got sidetracked by RL issues and just got a chance to check the posts. So I thought I'd save you from a quad post.
Good advice all the way around. The "user fee" is known in game as the country resources used, Dvd. When you go to your corp page, it's listed in both the monthly financials and in the profit and loss section. Whatever the value of the corp's product is per month, the corp pays 39.99% to the country it resides in. (But your state corps don't pay the resurces fee, so getting a CEO to buy them should bump up your cash flow.) So if you have a corn company in your country it isn't going to pay as much as a FacMaintCorp, and so on. Another plus for having CEO owned corps is that they have a higher quality cap, thereby increasing the value of product, which in turn increases the money you get.
One way to get offers for your corps would be to advertise here on the forum. Especially if you drop your tax to 0%.
Got my level 4, and now it looks like 5 is gonna be a bear. Keep those indexes up, you're going to need them as you progress. And I'll tell you, the more pop you get the harder it is to keep the health index up to snuff.
Back on the original track, the game is confusing in having a Defense Index and a Defensive Force Index. For your level 2, it's the Def. Force index that needs to be 75. The Defense index doesn't come into play until you go for level 5. Concentrate on garrisoning your Capital, cities, forts, towns, bases, and airports. If you're going to sell your corps you don't need to garrison them, if you keep them you need to garrison them too. When that's finished, the quickest way to bump the DFI is by buying and deploying Interceptor wings (400 interceptors and 12,000 missiles each) which are worth 1.39 points on your DFI. Helicopter wings (400 copters and 12,000 missiles) will add 0.86 per.
'Nuff for now.