The Market: Ok the "new" Shiva market, and new strategies. Pre-shiva, you were limited (forced) to buy your goods, deliver them, and sell RuneScape Gold while you were there, or put in a sell order and hope someone else docked and wanted that very item. Not any more.
Now, there’s a whole new world of buying and selling, and some VERY creative ways to do it. The marketing skill allows you the ability to buy (and sell) remotely! i.e.: you don't have to be in the station, or even the same system.
Now with a high enough skill you can manage your profits without ever having to leave the station.
Also, buy some GSC's (giant secure containers), as many as you can fit in your hold. They can be a "poor mans expander" if you get them cheaply enough.
Of note, the market supply and demand changes with every buy and sell order processed. When you sell something to an NPC the demand price "usually" goes down, as the orders are filled. And the buy price goes up as more is purchased.
Advanced Trade goods Strategy 1: Let’s say you find a good deal on those antibiotics we talked about earlier. But, they want over 100k of them, and you find yourself looking at 17 different stations selling just 8k vole each.