1) Recycling old Boxes
If you have many old boxes formerly used for carrying such items as paper (maybe look around school or offices for any spares) you can easily adapt them for storing bricks and models. Use more tape and card to create compartments for seperating parts! If you have the origional but tattered box for your model, you could even cut out the faces and stick them to the top of your box to remind you which model pieces are inside!
2) Use Organising Boxes/Transfer Cases
If you are looking for a low cost and easy solution for storing LEGO, you could purchase a few organising boxes/transfer cases to quickly and easily store your bricks. Use a vivid or stick-on labels to name your boxes if they contain the parts used in one of your LEGO models only.