Kept 500M RS3 in my pouch to stake with (this was like November 2014).
I kept doing a stake, and selling my profits instantly, leaving 500M in my pouch. For example, I'd do a 300M stake, if I won I'd sell the 300M and keep 500M starting stack in my pouch. I ended up having made $750 until I lost that 500M.
I then cashed that $750 into pokerstars, and turned it into $1.5k on the first hand on a cash table, then into $5k later that night. I cashed out the $5k and bought 2 bitcoins to gamble with on PrimeDice, and I ended up making 25 bitcoins profit in 1 hour the next day (around $10k). I went back to pokerstars and made another few thousand.
All in all I made about $25-30k profit in that whole gambling session, starting from only 500M RS3 as I kept getting lucky :L
But I was stupid and cashed everything back onto primedice and lost it all in about 30 minutes

Learned a huge lesson from that :L