Think we can just fill down from the starting cell
Assume the existing prices are listed in C2 down
Put in say, D1: 5% (type the "%" as well)
Then just put in D2: =C2*(1+$D$1)
Format D2 as currency, and copy D2 down
To copy down from D2, just drag the fill handle*
at the bottom right corner of D2 down
*appears like a little black square
Col D will return the new prices
Pointing at a cell, D1, will also make it easy if we want to revise the
percentage in future. We don't have to edit all the formulas. Just change
the value in D1, and the col D will recompute accordingly.