Not sure if this is any good but Banana Boat will be giving away free samples of 30+ fun in the sun for the next two weekends at 'hot-spots' in Sydney, Melbourne, Brisbane and the Gold Coast.
Melbourne details:
http://cms.mix1065.com.au/ARNCommon/getfile.asp?FileId=54181
Brisbane/Gold Coast details:
http://cms.mix1065.com.au/ARNCommon/getfile.asp?FileId=54184
Sydney details
http://cms.mix1065.com.au/ARNCommon/getfile.asp?FileId=54183
(But considering the listed Turramurra beach has been closed due to a serious lack of water and sand - You might like to try Tamarama instead) (MOD edit)
…Don't really know how big the 'sample' is but hopefully it's a small bottle rather than a sachet.
First link is showing Melb locations
Second link showing Sydney
Neither mention Brisbane/Gold Coast, have you got another link?