Okay so the majority of the people in guild wars have no idea how to make money. As most of you already know that is all I do
I started out with 3 gold and now have about 145 gold.
It is simple. You find hot selling items that have a profit Margin. I personally prefer mini pets just because they are constantly in demand and you can buy cheap or expensive ones.
For example lets say you have 3 gold spending limit.
Search "Mini" in the trading post and then sort it by lowest to high price. start with the lowest priced mini pets. Click on the minipets you want to buy and sell then instead of buying it instantly click the "Place custom order". Make sure there is room for profit and make sure you remember there is a listing fee. So lets say the highest offer for a Mini Forest Grub is 47 silver and 20 bronze. Make your offer something like 47 silver and 35 bronze and buy 6 of them. Once you get all 6 re-list them for 25+ bronze under the current lowest seller. So if the lowest seller is 66 silver 99 bronze you will list it for like 66 silver and 80 bronze.
If you do that correctly you should be gaining a profit of 9 silver and 43 bronze each. Total of 56 silver and 58 bronze. Yea I know that is not a whole lot at first but once you make enough money you will be able to buy high prices minis with a greater profit margin.
Use this tool to help pick out the best mini to buy and sell. Its basically a calculator that will tell you how much profit you can get for each one and it even tells you what the selling fee is going to be.
http://tpcalc.com/?redirect=namtar.com