Only you can determine how much more you are willing to pay. And the only way you can try it is to talk to the hobby guy. Like Minnflyer said, tell him that you can get it cheaper elsewhere. I wouldn't mention how much cheaper but that 25% would be a good starting point. If he lowers his price to where you feel it is acceptable (and seems friendly enough) buy from him. Do remember that you can get the product right away and you don't have to pay for shipping.

If he can't give you a reasonable discount then walk out the door if you feel that shopping with him at his store isn't worth it. You need to support the local economy, yes... but you don't need to support someone who is so stubborn that he feels that he can charge substantially more than the market. He is ultimately doomed if he can't find a way to keep business. The earlier he knows he needs to change, the better it is for him...

On the other hand, if you keep walking in that store to check out what's new and you enjoy the time you spend there despite not purchasing anything. You have to wonder how much that experience is worth to you.

I always go to a specific LHS because the people are friendly and the products are good. They are about 5-10% more expensive that other places and I already get a 10% discount. But to me, the value of the shopping experience makes up for the difference. In fact, unless they are significantly more expensive, or that they don't carry the item I'm looking fore, I always shop with them. I'd rather give a buck to someone I liked than a quarter to one I didn't.

I just bought a Y.S. Dingo yesterday!!! You guessed it... from the LHS of my choice.