Runescape Grand Exchange: Bad flip makes money after all... and experience!

Recently I made a bad decision with my Runescape investments.  I'm a low-budget investor who likes to flip commodities.  Usually make between one million and three million profit a day.  Problem is, outside of the gold I have tied up in flipping my investments, I keep spending as fast as I'm making.  It started when I decided to go for 99 Construction.  I nickeled and dimed my construction skill, until Jagex started hinting about their 2nd extra-experience-weekend.  At that point, I decided to jump into merchanting.  Took a 10 million startup, and began flipping.  By the time the weekend arrived, I had over 100 million gold (this is Runescape now, not real cash!)
That was just barely enough to buy all the oak planks I needed to dungeon-door my way to 99 Construction.  After that, I was too broke to build my dream home, so I kept investing in the grand exchange.  But before I got very far, they announced the Elite Achievement Diaries.  Well, I think of myself as a high-level player.  At least, my character is level 138 and most skills are decent.  So as a point of pride, I want to get ALL the Elite achievement rewards.  I had the Ardougne elite already, and decided the next thing I wanted was the super-enhanced Excalibur from the Seers Village elite tasks.  Problem was, my herblore level was abysmal. (Not abyssal... abysmal!)
It took weeks to make enough money to raise my herblore.  And even then, I Evil-Daved a skill-boosting stew for the last 5 levels worth.  Then back to home-building.  Still flipping on the G.E., and I'd started fishing and cooking Rocktails. 
It was the Rocktails that did me in.  I saw how well they sold.  Decided to take my current spending money of 20 million, and buy 10,000 Rocktail to flip.  Everything went well, right up till the time to sell them.  They sat for days, then the price starting tanking.  I didn't want to lose that much money.  So I pulled them out of the GE, and started cooking.
By the time I'd cooked 10,000 Rocktail, I wound up making a small profit, using some money to invest in Death Runes for flipping, keeping a few Rocktail for myself.  And with my current gold of 14 million, today I bought back the Armadyl Chestplate I sold for Herblore money. 
Yay!... I'm broke again.  Okay, so starting over. 
Oh, and cooking 10k Rocktail?  My cooking skill went from 95 to 97!  I guess it worked out okay after all. 
Bit of quick advice... for a small and steady profit, without a lot of risk, flip Maple logs.  I buy 25,000 at 2 gold below median, and sell it at 2 gold above median.  I make 100k Runescape money every buy/sell flip.  It may not be much, but it's an easy way to get started.  The risk is low, and they usually sell quickly for me (bearing in mind the GE 4-hour buying and selling delay.)