I started my real Lego collection since my 4th birthday. Actually I've been playing with some blocks even before I was 1. Mommy got me the foam blocks before I can crawl, then a wagon of mega blocks just before I can walk. I remember I brought some of the mega blocks on my first road trip to Florida after my first birthday, and I really enjoyed my trip :)
Knowing that I like to build something, I got some series of Lego Duplo (for age 1.5-4), and I've been loving and playing it since. On my fourth birthday, Bebe gave me the 'pirate' Lego. which is so cool. The pirate has 2 swords and has a treasure chest that can be opened and closed, complete with the jewel treasure inside! The instruction let me make this cool pirate ship that can move its flag.
Daddy also bought me this Lego - Creator series. It is the Lego collection for 5-11 years.(Seems too advanced for me :)) They have all kinds of transportation you can transform into 3 kinds in each case, and Daddy allows me to disassemble every other week and make another one. I have 4 cases now.
Daddy and Mommy found the cheapest price at Target and ofcourse The Lego Land, but unfortunately The Lego Land doesn't carry all the series. So everytime Daddy or Mommy go to Target, they always checked it out for me. It's only $5.54.
The great thing about this 'Creator' is that it is packed in a small hard plastic case, so it is easy to store, not like the other regular Legos that are put in a cardboard (Only the Bionicle has the same case)
With my tiny fingers I learn to construct some cool transportations, and Mommy teaches me to read the instruction so I can make my own, and I did several times without supervision.
Anyhow, it's not too advanced I guess :)