I've been playing my two "main" alts on VeCo and Cael in roughly equal amounts over the last week. My Tauren hunter is now level 21, with cat and carrion bird pets keeping mostly up-to-date. On Cael, my warlock is now 19 and a bar or so off 20. I want to hit the BG's a bit before he dings. The bank alts are both level 12 or 13 and are getting desperate to see some scenery other than the path between mailbox and Auction House.
The economy on each server is quite different. VeCo Horde is an old, established realm with lots of level 70's. There are also a lot of lower level alts, but apparently few genuine newbies. This means prices tend to be higher, but more stable.
Cael on the other hand is a newish server. I think it opened around Christmas time, originally only for transfers. I created my first horde alt there about a day after it opened to new characters. Of course, my alliance characters are brand new. The server is frequently at "full" or "locked" status so is plenty busy! The Alliance auction house often has over 22,000 (500 "pages") of listings, roughly double VeCo and Dath figures. There seem to be lots of genuine newbies. This means that there are lots of really dodgy prices for items on the auction house and a whole lot of undercutting going on.
At about level 15 on both servers, my "main" abandoned one of the gathering professions to take up enchanting. The Tauren hunter is now skinning/enchanting and the Gnome warlock is mining/enchanting. The bank alts remain skinning/mining.
I invested nearly all my money back into the auction house on both servers, looking for cheap items for disenchanting. Fifty gold sure buys a lot of crappy greens! I was specifically looking for items who's bid or buyout price was no more than 3/4 of auctioneer's lowest disenchantment value. There were relatively few bargains to be had in immediate buyouts but a lot of items had really low bid values. The mailbox on both bankers nearly exploded with the number of incoming messages.
After I cleared the mailbox of all the "outbid on..." messages, I collected and forwarded all the disenchantable items through to my mains. Disenchanting by itself is not sufficient to level enchanting skill, so I had to use some of the resulting materials. Any remaining materials were sent back to be auctioned. Since I have been adventuring with these two mains and still sending back all the stuff I gather while travelling I'm not really sure how much of their money has been due to disenchanting only.
I also got sick of running out of bag space and have blown large amounts of cash on netherweave 16-slot bags. I think all 3 slots on the hunters and 4 slots on the others are now full of netherweave bags. If not, I'll be getting the last ones soon. On VeCo I was lucky enough to meet up with a guy who gave me a 50 gold donation after I farmed up a bunch of leather for him. On Cael, a nice girl gave me a 14 slot bag, which I have since returned after my upgrade.
These two gifts sort of invalidate my experiment in self-sufficiency but then again, WoW is a social game and using social contacts to help advance is almost a necessity . In both cases the value of the gift is fairly trivial compared to my net-worth at the time anyway.
Despite the gold-sink that is 7* netherweave bags and levelling enchanting to at least 75, both sets of alts have net worth of about 175g as of last night. VeCo is slightly easier to manage due to stable pricing.
Lots of money has come from reselling vendor recipes. Some came from the mining of copper and a bit of tin but this is less now on both servers since I've been concentrating on other things. Selling enchanting materials is starting to build up but I still need to use some of these myself to level up. A relatively small proportion of my income has come from buying and reselling stuff in the auction house.
At this stage I look to be on target to get my level 30 mounts as soon as they become available. If Bliz does not introduce those, then level 40 is looking good as well, with money to spare!