I usually don't have trouble getting a couple of pounds up here in Michigan, but then I haven't been shooting as much as I used to, so I don't have to look quite as often. I'd just try to order in bulk if you can swing it, if there's not any nearby. I did the math once, and to me, the magic number seems to be 10 lbs. At 10 lbs from Graf's, it was like $16.60/lb. but I had to order nearly 25-30 lbs. before the price came much below $15.00/lb. Oh, you probably already know this, but in case not, make sure you ask the guy at the counter. The Holy Black is classified as an explosive by the ATF and must be kept behind the counter in a safe/powder magazine. I didn't catch that piece of information for a long time after I started shooting bp, and it took a while to get good powder.
You only take one shot at a time - make it count.