I don't have a dress form. :(
Now looking online, dress forms range from 100-300$ and how do you adjust them to your size???
Here's what you need:
-REALLY good scissors
-at least 2 rolls of duct tape (mine were 20 yards per roll) I used yellow because it was just as expensive as the grey and it was yellow!
-2 plastic coke bottles.
And here's another great picture guide, it's in German, but still a very great tutorial:
-T-shirts are better but a tank top will also work