The great thing about this tradition is there really is something out there for everyone. You like yellow bell peppers? There's a button... Birds in a Nest? There's a button... For really unique ones, like Zachary's microscope for this year, I go on-line. Here are the ones I found that have some great buttons or charms.
As Cute As A Button
The Button Drawer
This is where the most pewter charms are found. They are mostly under a dollar and they have so so many!
This one is a new one for me but it looks like it has a lot of the ones we have gotten in the past.
Also a new one but thought I would include it