I've used AmmoSeek.com a few times when I was on the hunt for .223 and 9mm ammo, and I found it pretty handy. It really does pull together prices from a bunch of different retailers, which saves a lot of time compared to browsing each site's inventory. The prices I found were generally competitive, but I did notice some sellers that seemed a bit sketchy, so I recommend checking their reputations or reviews before buying. I also had a couple of listings that weren't fully accurate on availability, which can be frustrating, so I suggest double-checking with the seller directly if you're unsure. Overall though, it's a solid tool to find the best deals, just proceed with a bit of caution.