I have two characters and a bank alt. My main is a level 80 Troll Hunter (For the Horde!) with 450 Mining, 450 Herbalism, 500+ Fishing and 450 Cooking. My only alt is a 72 Death Knight (never took the time to level it past there, he's mainly for professions) with 450 Elixir Mastery Alchemy and 450 Inscription. I also have one Bank character who deals with selling the many relatively low value glyphs I sometimes produce, and other odds and ends. This character also does some buy low-sell high stuff, but I do less of that now that my professions are bringing in more cash. I rarely farm, so Herbalism and Mining are essentially useless, but I havn't chosen new professions yet. Its always good to have Herbalism in case a certain herb that I need for alchemy or inscription is insanely overpriced.
The server I play on (which will remain a secret) has a very inflated economy, from what I can tell. Most items range from slightly to much higher in price than on other servers. Because I don't farm, it doesn't really affect me. Most of my techniques can still work on your server because of one simple "rule": when the cost of materials goes up, the cost of the final product generally follows. However, its always a good idea to check your server's prices before following my advice word for word.
As much as I'd like to, I can't spend my entire life on the internet. I'm going to try to post as often as possible, and regularity may vary due to my schedule.