Since I roll my own I don't purchase ammo online but you can also ask if they price match.
I was looking at purchasing a set of tires for my car yesterday.
The online retailer I normally buy from was out of stock so I had to look elsewhere.
I found a pair in California. They wanted $375.00 per tire which included free shipping but didn't include the $20 handling fee for the pair so the total price was $770.00 out the door. The problem was that it would take 5-7 business days for the tires to arrive here.
I called another company which was showing the tires as in stock. Their advertised price was $406.00 a tire plus $36.00 shipping for the pair.
I had their employee confirm that the tires would be shipping from their warehouse in Ohio and would arrive in 1 day at their destination.
I then asked him if they price matched and he said sure as long as the product has the same manufacturers code and they could verify that the price was being advertised elsewhere.
I pointed him in the direction of the other companies website and I should be getting my tires today instead of in 10 days from now for $78.00 less than I would have paid.