Um.. I disagree. Please keep in mind that you really compare lfs with online shops. Most regular online shops are more expensive than our vendors as we'll. lfs has much more overhead. And their customer base is much smaller. It's going to take much longer for they to sell these more "exotic" plecos. Incurring additional cost and taking on a lot more risk at the same time.
Yes, you get a l240 for half the price if you shop around online. You'll still have to pay shipping for a fish that you don't get to inspect personally. Considering you don't have to deal with shipping charges, possible doa or just general stress from the shipping process, getting to inspect and choose the fish. The prices are not THAT bad.