There are many money-making techniques that OSRS Gold have a tendency to last forever In covering the never-ending supply of certain products like the gathering of raw materials, to fight monsters of different strengths to find rare drops and then finally using the market to invest vast sums of money to make more money.
Of these, collecting raw materials is the least expensive but will require constant work. It's profitable, however, you're basically working so other people reap the benefits. It is risky to kill things and there is a risk of loss , but it's usually a hell of a lot better than collecting raw materials. It might, however, require personal experience, information, a higher combat score and a large group in certain cases.
Trading in the market for the economy requires the right knowledge, perseverance and a starting amount of gold. You can buy items for a low price but then later purchase at a higher price. The idea is straightforward and although you'll have to be aware of the market frequently this is the one that takes the minimal amount of "work" however it requires you to be patient, make the right choices , and not be in a panic.
If I was in your shoes I'd be willing to spend those 28 million and either make a bet in the economy if I knew how, or simply to really work on your combat stats and focus on killing objects to get loot. There's a downside... that the highest reward drops usually requires stats way above yours and you'll need to work hard on combat for a while. What's the issue? If you use your preyer book instead of the normal preyers, you'll get preyers of the book of your god.
Okay, everyone is aware that illegal gold trade and RS Gold 2007 the indrect problems that it cause (autoers) is a major problem for Jagex and a matter they've been fighting for ages with little results.