This set up did not cost alot. I am big on trying to keep things cheap since I do have such big parties.Here is the cost run down.
Capri Sun boxes- nothing (He takes them to school everyday so I just saved up.
Colored Paper- $6. I saved bought at Party City and Dollar Tree for a $1
Foam discs- $4. I also got these at the Dollar Tree, they are called floral plugs and I cut each one into 3 1inch pieces.
Lego Poster- $7. A friend of mine created it and them I printed it as a 16x20 at Costco.
Lego Man garland- Free. I already had purchased the pack of paper to make the gift bags. And I also already had the embossing thread, but you can find these at any craft store for around $1.
Hostess with the Mostest. And the Lego man stencil came from zakka life's site.