Well, I use a roll-on from Aldi. I was sceptical at first becuase I am heavy sweater and get smelly easily too. But I've found it not only effective but cheap too. It has a gentle sweet powdery smell which is in no way offensive.

The roll-on comes in a mauve bottle (there aren't many options at Aldi so it won't be hard to find!) I would recommend it for anyone looking for an effective AND cheap deoderant.