What is the best way to remove bunions, callous, and corns surgically? And generally, how much would it cost?

There are many . Different types of bunion surgery. The choice of procedure depends on many factors including how bad a deformity is present and the patients expectations for rehab. Corns and callouses could be trimmed. Again, depending on where they are located surgical procedures can be performed to eliminate them permenantly. Get a podiatric consultation.
Bunion surgery. There are no braces or exercises to get rid of a bunion. If you elect to have it surgically removed, there are several ways your surgeon could go about it. Depending on the angle of your bones (you'll need an x-ray), there are many different procedures to choose from to correct your foot. Once the bunion joint is corrected, the calluses will often go away over time, depending on their location.
See below. There are many causes of these deformities and many different surgical approaches. Cost varies and would be impossible to tell withour knowing specific procedures to be done.
Options vary. It depends on the location of the deformity and the severity of the condition.