I have the simplest problem to solve and its giving me the biggest headaches.

I have a column of product prices (say: column B) and I wish to add 10% or a
fixed value of 0.1 to each cell in the column. I want to store the results in
the same cell that the initial number was sourced from and that the formula
runs in.

e.g. Cell B3 value 6.34
I put a formula in cell B3 : =b3+0.1
I want the final value of 6.44 to be stored in cell B3...

Is what I am trying to do possible or (as I suspect) will I need to involve
more cells/columns?

Many Thanks in advance for the advice,

Dave