Our sons love Lego and although they are very quick to build from directions and proud of their accomplishments, they more frequently build from imagination. Just last night they built the Tower of Pisa so that one of them could show it off at his CC presentation!
Lego has been a staple in our family and I am certain that the boys spatial skills, fine motor skills and math skills are where they are today because of Lego. Following the directions is a great discipline, but a small bucket with Lego can become so many different things.
Our boys 'trade' Lego and they and their friends have created a whole system of money made out of Lego.
We are also involved in First Lego League which is a great way to combine academics with fun - and fun they have as they meet weekly with other like minded youngster to solve a real world problem in a simulation environment using Lego....
As for getting more Lego, one box can really be the starting point - a good value buy is a simple bucket of mixed pieces that most larger stores sell. Garage sales are of course a great place to find them and if the Legos are dirty, just put them in mesh bags and run them through the washing machine.
This month Lego website has some great deals, and TRU usually have a buy 2 get one free each fall.
Good Luck
Christina