Pine Bark Fines sources
I'm in SE Virginia, AKA Tidewater. I haven't seen the question here, but in case anyone is looking for potting mix constituents, I've had success at 2 places. The first I can't tell you the name of; it's a mini-mart that has a small fenced-off area of plants - generally good quality, but small selection. They carry the pine bark fines in 2 cu ft bags that run about $4. Find the store in Bayview (Norfolk), at a "V" shaped intersection of Bayview Blvd and Fishermans Rd. You'll see on the satellite picture of MapQuest that you can turn into the parking lot from either road. Approach by Chesapeake Blvd, or if you are familiar with the area, Old Ocean View Rd. might be preferable.
The other place is Pioneer Southern, AKA Good Earth Organics, 310 Kenyon Rd in Suffolk. 757-539-7489. They sell wholesale generally, but I got some leftover bags off-season a few years ago. I think this could be a place to try if you want it by the yard. Or maybe they would steer you to their retailers. I had no luck getting a call back after leaving a message off-hours last week, then found it at the place above; I suggest trying them early in the day when someone might pick up.