A lot of this has been covered, but here's my take:
1) I wouldn't have pushed the issue if it was an honset pricing error (it doesn't sound like it was). I'm not going to take someone for a ride because they meant to make a tag that said "$100" and it read out as "$10". Mistakes do happen.
2) This guy's excuse for a "pricing error" was nullified by the statement where he said prices have gone up. He didn't pay that much for the product, wasn't originally intending to ask more than he wrote on the box, no one was buying that product, and he was just trying to bring the price back up to market level... He bought cheap, and still turned a profit (he just felt he should be able to make more of a profit). You didn't take food off of his table, you put an extra $45 on his table, minus his overhead and purchase price.
3) Customer service is clinging by a thread at many small stores, which might explain why many small stores are barely holding on. I'm far more likely to shop at big-box stores these days, just because the service is so much better.
4) I can't stand when retail stores raise prices on inventory on their shelves. I've had places tell me "hey those widgets are going to go up in price $10 with our next shipment", and that is fine... prices change as wholesale/shipping prices change. What I really hate is when the widget that they bought for $10, which they were selling for $15 today, gets re-priced to $20 tomorrow just because it hasn't sold! I don't consider this the same thing as commodity price changes, which are always fluid. It isn't like you were buying these bullets as bulk pounds of lead, or barrels of oil... It was a value-added retail product.
5) I wouldn't recommend you go back to this place. Hope you don't mind, but you burned a bridge (whether you like it or not). Sometimes I won't push an issue at a store I like, just to avoid burning a bridge. Other times it just isn't worth it to go back, so I might speak my mind on an issue I feel righteous about!
Ultimately, it sounds like you guys both pushed harder than you should have. But, you came out on top.