Chances are your local storage facility has blank newsprint. I find it cheapest there and use it in lieu of printed paper. In my store it is for wrapping purchased items placed in bags as well. I leave it out like a mat at the sales counter and wrap as needed.
I, too, order supplies off Ebay especially peanuts. And if you know someone who is an Ebay seller that gets their "coupon" for shipping supplies free, they might throw some poly bags your way. Local Flea/Swap meets I can find packing tape pretty cheap too. Every once in awhile my local 99 cent store has padded envelopes I stock up on and in a pinch I go to local pack and ship stores for peanuts. Use friends and family! Let them know you need supplies! I get boxes from my sister's restaurant, have a friend who brings me huge boxes of bubble wrap and peanuts from his online purchases too.