im not even sure what thinkgeek is but since you said shipping i tihnk your talking about music equipment like guitar and stuff. if thats so go to musicians friend
You can froogle each item on thinkgeek.com and see who else sells them. Some are unique to that site, but a lot of the products they carry are carried at a lot of other places (and usually for a fair bit cheaper) I'd just froogle it on an item by item basis.