Worksheet problem

I need to add a function to a macro that will take any "repeated" words out of a list of unknown length.
A spreadsheet lists transactions with the account name in column A. I would like to just show the first occurence of this name so that the list would look like this:
cars 10 | instead of: cars 10
20 | cars 20
15 | cars 15
buses 1 | buses 1
5 | buses 5

I do not know beforehand how many transactions there are in total (so I think I need to use an array but am not sure).

I was thinking of something that says if this cell is the same as the previous cell replace with " " else move on to next in list.

As you can tell my skills are somewhat basic - please make it simple.