Peace Fleece worsted is a heavy worsted. If you order it wholesale (and anyone can as long as you meet the minimum order - you don't have to be a business) it's $4.50 per skein and the shipping tends to work out to be about 25c per skein. You have to order $100 worth of product at a time to get the wholesale pricing (it can be more than $100 ) and they charge actual UPS shipping.
The website is peacefleece.com - the worsted is a wool/mohair blend and it washes up really nicely. They'll also let you sell items made from their patterns as far as I know, which might also be useful to your group. They have a natural color that isn't bleached as well as many solids/heathers.