Alternative Price field in Admin, 4 column Product layout, Remove Product prices, Text changes

1) This Error message must be fixed: "Warning: Division by zero..." 2) I need Product Prices not visible in the product listings until the user actually clicks on the product listing. 3) I want all products to be displayed in 4 columns (right now a few of the categories are in 4 columns and a few default back to 3 columns.) 4) I need an additional field in Admin when creating a New Product. The new field will allow user to Add a Price. Right now I have the "Display MSRP & Savings" contribution used for Product price. I WANT TO KEEP THIS CONTRIBUTION TOO. I need the alternate way to add a Price to work also. So in otherwords, the Administrator has the option to either enter the price using MSRP @ Savings contribution OR they may manually enter the price in this New Field labled "Price" 5) A few other minor text changes will also be required. For the "Display MSRP & Savings Contribution" the text shown on the screen as "MSRP:" should be changed to "Price:" and the text beneath it "Our Price:" should be changed to "Sale Price:"