I live near Philadelphia too,
Home Depo
Lowes
Walmart
most hardware stores
they will be getting their new shipments for fall in any day now.
Check them out.

I purchase Turface at Fisher and son in Malvern.
http://agmap.psu.edu/Businesses/1466

Hilltop Distributors in Media carries poultry manure, green sand and other products

http://www.contractorssolutions.com/HilltopDistributors.htm

You could probably have things delivered from Penn State Seed Company
http://www.pennstateseed.com/

They sell Bio-Comp, a wonderful growing medium made from bark and peanut hulls. They sell Perlite, too.

http://www.pennstateseed.com/index_files/Page528.htm this is a list of some products.

Try Primex in Glenside. They have everything.

I never thought to check Penn State Seed, thanks Carol. This past summer I needed more perlite than the tiny bags the box stores (maybe) carry.... I ended up giving up on the project instead of paying for the overpriced little bags. Now I may have to re-activate the project for next year!

Serves me right for never actually going into the PState store. Never judge a book by it's cover!