It is possible to make gold with out any addons, but addons really do make it easier. I generally use the curse client to download items. Alternatively, you can download addons and manually install them in your Addons folder. On my PC, the folder is C:\Program Files\World of Warcraft\Interface\AddOns.
An addon to price stuff : Auctioneer primary website or curse. This is also a good all round posting addon too.
Crafters need two other addons:
- Addon to tell you what you can learn (and where) : Ackis recipee list at WowAce or Curse. Not only that, but you can open every recipee as a tradelink to see the components.
- Addon to tell you what should sell for a profit : LilSparky's Workshop at WoWAce or Curse. It does this by using pricing data from another addon like Auctioneer to get buy and sell values.