If you'll refer to the post right above yours youll see the answer to the "f2p" aspect of this.
P2P with little to no quest reqs, white berries at red dragon isle are good for money, and you can telegrab or just pick them up if you dont have mage.
Flax of course, and spinning bowstrings if you have the patience.
Its hard to be successful flipping without a lot of money. You have to do it the same way i detailed earlier in this thread, but you won't see much profit.