Hi
Yes, you are right. You need to use cross tab report to achive this requirement.
First you derive start date and end date.
In Record Selection use below to filter last one year data :
Database.datefield >= date(Year(currentdate)-1,Month(currentdate), 01) and
Database.datefield<= Currentdate
Now through Insert menu insert cross tab on report header or footer and in columns place 'Database.datefiled' -- In group options set it for each month
In Rows add 'database.inventoryItem
In summary field add Sales value