Guess what, many online vendors do the same thing! I've had this happen to me with Amazon.com even. Checking the price on an item I want and not ordering it until later in the day, or the next day, and the price jumps up - at check out. If I don't buy it for a week or so and check back on it, the price drops again.
Not quite the same thing as what you're experiencing, but similar. If they know you want it, they'll kick up the price at check out. Can't do that at a retail store. Unfortunately, there are fewer and fewer of those of the kind of retailers that deal with sporting goods these days. Maybe you should try to contact them by phone and/or email to find out what's going on?
"A voyage in search of knowledge need never abandon the spirit of adventure."