Filthy rich: Anything over 100.000.000
Rich: 50.000.000 - 100.000.000
Upper Middle class: 10.000.000 - 50.000.000
Middle Class: 1.000.000 - 10.000.000
Anything under that is poor
It used to be special when you hit 1mil. But that is so easy nowadays.
Assuming we're going by wealth (as in value of inventory through sites like tektek or painstakingly long addition through the MP)
<15mil = poor
15-30mil = lower middle class
30mil - 50mil = middle class
50-70mil = upper middle class
70-100mil = Rich
+100mil = John D. Rockefeller
1bil or higher = Seriously, you need to reconsider your life and priorities.
For the most part, unless my friends or I am questing, I usually have less than 150k on me at a given time.
Gold as an asset is hella easy-come easy-go, so I'd advise just picking out some stuff you want and then saving up for it, rather than worrying about how much gold you oughta have in your account. Items are the fun part of the site, after all.
The amount of gold I have, for instance, waffles between zero and a million from month to month. This fusses me not at all, because I am slowly creeping up on an inventory of 3,000 items. It's allllll about the stuff.
It's hard to gauge what's considered rich or poor. Just because someone has a flashy avatar doesn't mean there rich. They could have spent all there gold on that avatar. If someone looks poor, they could just be saving up for there dream avi. You can make really super cute avi's for 150k or less. I would suggest making a dream avi, then you can see how much you need to save. Also you could try getting some basic staple pieces, like jeans that you could intertwine with some more of the pricer items to make something cute. Making a wishlist does help, too.
If you want to make some extra gold try going around towns and pick up some trash, flowers, and bugs.