Both of my mayors have over 100 million in the bank and each of the other 3 characters in each town has 20 million in the bank. My sister now has her own game (rather than playing as one of my extra characters) and I've given her maybe 30 million. She has made 15 million on her own from fishing (which she loves doing). I consider myself rich in NL (not IRL), but I still look for the money/gem rock each day and sell items to Reese. I go to the island almost every night and catch beetles, but I do this to relax not to make bells (but I do sell them and make 300,000 - 400,000 each basketfull).
I'm definitely rich by my standards. I have a lot of bells and rare items, but that's because I play A LOT. A LOTTTTT! And I spent a lot of time trading/selling turnips/island hunting. So after a year of investing all that time, I have a lot of bells/items to show for it. I don't dupe, so I feel I've earned it all (even though I've probably paid for some duped items along the way). But I'm sure there are dupers out there who have a million times more than I do. I don't compare myself to them though. I'm happy with what I have.
I guess I'm pretty rich. I've been doing a shop recently and have gotten lots of Bells doing that. I had 2 million Bells at the time (which is nothing to others, but a lot for me). I paid off a ton of mortgages. I just finished my basement, but I think I have one left so now I only have about 500k. I don't care too much for money though; it's not everything. Whenever I feel in the need for some extra cash, I just beetle hunt for a bit It's really no big deal.
I'm happy to have enough to pay off my house--ON my house, I should say. It still hasn't been paid in full. I spend money cataloging the new items of the day and save the rest to rollover the following day. If I hit 100k, it becomes a house payment. I have maybe 1.5mil in the ABD, but I haven't deposited anything in forever.
Wealth doesn't mean very much in Animal Crossing. In a few hours I got 3 million bells from beetle-hunting. Just today I got another million by taking 5 or 10 minutes to sell turnips, which I'm using to buy more turnips, which will get me millions more.
For me it fluctuates though, I used to have a few 100k to my name, then all of a sudden I have millions, but it'll be gone soon as I plan on spending it on expensive things.
I've been playing since release day and have a billion bells now.
Never sold but do buy items. All bells were made by getting bugs in the beginning and than turnips and perfect fruit.
You just have to have a good group of friends that shares premium and high turnip prices.
I give away bells to new people on the island. Ones that aren't begging for bells.