My impression is that they have some sort of price alliance and ask for about the same price for similar stuff.

That is good because you can bargain at a bunch of sellers and practice “walking away waiting for them to catch you” to find out their lowest acceptable price. On the other hand, it will be hard for them to go below that well accepted price.

I’m really good at ignoring people – meaning not looking at or hearing those sellers. You’ll have a hard time if you cannot do this. Bringing along guys definitely helps.