Maybe 200m. Back with the old RS system, I could make 5m some days. Was fun too, like 20 people on MSN in RS chats and when the shops stocked everyone would spam "RS RS RS RS" and I'd have like 10-15 shops open
This was 10 years ago, though. 200m worth of items then is a lot more now, for example I had RoSN, FSS, T-Tear etc.
Before I "quit" I spent all my np in upgrading my shop massively and stocking it then didn't play for 5 years. Then when I came back I got iced for "buying np" and decided to play illegit since then I've lost close to a billion. Currently have about 110m extremely secure/safe.
40 mil and 4 High-end UC's. I didn't have many neofriends, did fair trades, and only had 1 account which I logged onto from 1 PC. I spent hours restocking, snipping, and trading each day. I didn't chat on neoboards, and just kept to myself. I somehow got iced for cheating on games, when in fact, I never played a single game.
Its not whether you'll get iced or not, but how soon.