This is because all items have the same ID, all items use either 0 or the ID column is empty. each item should have a unique ID
This is because you entered the price with the leading $ in the add to cart button. the dollar sign should not be included in the add to cart button settings
again, in the add to cart, you enter the weigh with oz. you set the weight units i the cart object, and should include that in the add to cart button.
I turned on error reporting for the checkout page and it returns the following error:
Parse error: syntax error, unexpected '@' in /home/sankeerth/public_html/test/confirm.php on line 33
this usually hopes if you use one of the presets for storing order details and summary, but you already have those tables in your database base and they do not have the same format.
delete the checkout pages, and delete the order / order details tables in your database, then run the checkout wizard again to recreate them
Taxes and shipping won't be calculated till the checkout page posts to the confirm page.