What are his measurements?
I have found tiny tiny clothes at Wal-Mart, Target, PetsMart, Old Navy, Petco, etc. --- all cheap!
PetEdge also sales tiny clothes XXXS, etc. and they are cheap.
I think someone had post some XS and S boys clothing in the for sale section today or yesterday - check thru that thread.
Also, check the featured sellers section and click on their website link in their signature and check out their sites...a lot of them have some really great clearance sales going on.
I sold all that I had a few months ago....
Good luck