Well to start with just buy whatever bags you can afford. On the AH you will see small pouches and linen bags for a few silvers each. I would seriously look for a guild to join, there are often guildies who will make bags for next to nothing for you. You should sell you skins on the AH, they WILL NOT sell for as much as copper bars but they will sell. I personally only sell on Fridays and Saturdays when a lot of weekend players are on.
regarding herbalism or mining I would like to say that at lower levels mining is far more profitable than herbalism. Copper bars sell well, peacebloom not at all. However as you go up in skill the balance changes. Top end herbs sell far better than Thorium. Even with middling skill Wildvine, Swiftthistle and Kingsblood can bring in better profits than iron. It might, and I mean might, be worth learning mining for your first 15-20 levels, dropping it and picking up herbalism. All gathering skills level quite quickly.
I would also consider creating a "bank Alt". A character that you get to level 5 then move to the bank and leave him there. When you real character is out adventuring and fills up her bags, instead of heading to a major city you can just mail you stuff to the bank alt who can then put them on the Ah for you. Remeber that it takes 1 hour for mail to arrive, though if you just send money it is practically immediate. You should also think about training your alt in enchanting, to disenchant any green equipment that won't sell, and leatherworker to convert andy ruined leather scraps you skin into light leather.
Oh, and remeber to buy a skinning knife from a vendor, they are 81c.
Edited, Sep 21st 2006 at 7:58am EDT by magret