Our ACS supplies all luminaria materials and this year when they ordered the bags, they had them shipped directly to my house. I picked up the candles and cups at our local ACS office a week before our event. I've been luminaria chairman for 2 years and enjoy this committee. After two years of rain during the luminaria ceremony and dealing with soggy bags who's bottoms give out with the weight of wet sand, we're done with the sand. Next year we're asking each team member to bring a small canned good to put in each bag. The candle/cup will go on top of the bag. Canned meat is perfect but small cans of veggies would work fine. In the morning, we toss the bag and candle and will deliver the canned goods to our local Food Pantry. No mess, no fuss and our community will reap the benefits of the donated goods.

I found a local restraurant supply company or a  paper company.  The usually deliver bags and supplies of that nature.  What I use are referred to as "No. 8 bakery bags"  ULINE is a company that has these on line.  You can look up the specs and then approach local vendors.  I had a restaurant supply some and then other places can also help out.  Good Luck