We all have to start somewhere, scrappy quilts are a great way to Use up the stash you have for sure. But if you don't have a stash to pull from you can still make your quilt very scrappy looking, it simply means you will have to purchase it all (small increments are great here) or trade with others. Sounds like you are off to a great start. Yes, the method of pulling from a light and a dark sounds like it will give you the contrast I was talking about with what you have.
Check out your thrift stores. I know many that get a lot of their fabrics from there either because someone has donated fabric or because the buy cotton shirts and cut those and use the. I have not tried cutting shirts but its a great way to re-cycle and again build a stash with less expense.
Have fun creating,
Muriel