There are plenty of natural ones to be found - even in normal supermarkets. I like the idea of the one that is like a stony/crystal type thing (great explanation, well done me!!)
I used that years ago and it lasted a year and worked better than any deo. Didn't know they sold it in supremarkets though.
EDIT: £5 for a whole year!
Maybe I saw that particular type in a health food shop. Definitely can buy the paraben (sic?) free, natural roll ons at supermarket that begins with J as I bought them for my children.