Help with shared worksheet protection....

Thank you for responding!! If we do "read only" or password modify, will people still be able to use the sheet.  It is being used for shipping calculations so there are columns where whoever needs a shipping quote can put in the weights and dimensions of the shipment and then the other columns have formulas that will generate an approx. shipping quote.  Will people still be able to do this?  We just want to ensure that when the spreadsheet is closed, when the next person opens, the prior user's weights and dims do not get saved causing potential overlap and thus miscalculation if they don't see the columns were already populated.  Thanks again :)