We have had a difficult time obtaining red racquetballs, but have finally found a source at Bal-A-Vis-X (
http://www.bal-a-vis-x.com/products/orderform.htm). A dozen red "SkyBounce" racquetballs cost $12.00, and shipping from Kansas to Massachusetts added $3.60. We paid via PayPal, and shipping was prompt, but with no order acknowledgement before receipt of the shipment other than PayPal confirmation of payment.