Business Expense deductions by Entity?

[Link McGinnis]

It appears from some reading that different entities are able to claim different business expenses against income.

Can someone explain the differences in the allowed business expenses that can be deducted when using LLC (filing as S-corp), vs. S-Corp, vs. C-Corp?

I'm more familiar with C-Corp and it seems anything we purchase to help in our business (down to tape dispensers) are considered an expense. Is this true with LLC filing as S-Corp?

Thanks!