You wrote: "I find it hard to believe that the store did not have advance notification of the impending reduction". You may well be right but why should that make them want to tell you about it? As employees of the company, it's their duty to seek to maximise the firm's profits. Probably far more importantly, from their point of view, they'd also like to maximise their commission. It's very rare that you'll find a company employee telling customers about forthcoming price reductions. Most firms would probably regard it as a disciplinary offence if they did so.
There's absolutely no chance that you'll get a refund because the price went down.
Chris
PS: I know how you feel. Last year I was tempted to take a flight to Barcelona. The price of the outbound flight was just �19.99. I couldn't make my mind up for a few days but I kept checking the price and it stayed at �19.99. I finally decided to book the flight and found that, in the few hours since I'd last checked the price, it had gone up to �29.99. I kicked myself for prevaricating but I still booked it anyway. I consoled myself that I'd got a much better price than if I'd left it a few days longer. So, a few days later, I checked the price again to see how much I'd saved. The fare was now 49p!