I guess it would depend. If i buy something at Target and it goes on sale within 3 days or a week, and it's worth the hassle of me going back, they usually will credit you the difference. But like i said it has to be worth it.
Example, we bought a big screen TV and less then a week later it went on sale for $500 less...Back to Best Buy I went and they credited the $500 back to us.
I bought Mary Lockwoods turtle tutorial, because I am doing the help the turtles of Cozumel. The day or so after I bought it, she was giving it away for people to use to make turtles for my cause. It was a bummer but hey to me..regardless $30 well spent
Each person has to do what they think is right for themselves. I would never expect any kind of refund for something that I bought 3 months ago and then it went on sale.
Just my opinion
Becky