Insert a column right next to the existing price column. Create a formula in the new column at the very top next to the first price that looks something like this
where A1 happens to be the column that contains the current price. Now select that new cell. When you do, you will notice a little plus sign in the lower left corner of the cell when you hover your cursor there. Double-click it and it will copy the same formula all the way down the column to reflect the price to it's left marked up by 35 percent.