I was in Walmart today, I went back to the electronics section to check out the CD's. I noticed there were less CD's but next to them on a wall, there were CD's on SD cards (same price as CD's). With them was an SD card player, with ear buds for $20. I was wondering if anyone has heard any of these SD cards, and what their sound quality was like? I have noticed more and more stores carrying less CD's these days. Think this could be the replacement? If not then what?