I looked at your link and it's mentioning of paying $129 - forget that as it's too expensive. Plus, what is this "press" thing?

Again, you don't need to pay for the distribution service; you can do it yourself if you want to save the money. But the articles on that site will tell you most of what you need to know to write and distribute a press release. That's an important step, as it's one way to get your game mentioned in magazines and on larger gaming websites.

I was told not to use download.com and to use Regnow instead. I often don't think of Tucows as I almost never go there.

I think we're talking about different things. You don't need to sell though these services; most download sites (and there are many good ones) will allow you to list your product there for download, for free. Download.com and Tucows are large sites with lots of traffic. We always upload there.

(BUY/DOWNLOAD) What do you mean by this?

Check out the articles at Dexterity that I mentioned. But in particular, conventional wisdom suggests that you should have big, bright buttons for the two most important actions -- downloading the demo and purchasing the game.