Hello Ross,
It is possible to get help with children's projects. Have a look at this scheme run by the RHS:
http://apps.rhs.org.uk/schoolgardening/teachershome/news/reciproc8-freeseedstools.aspa
I would also recommend keeping an eye on special offers eg free packets when you order a few from a company. Many gardening magazines give away free seeds from time to time as well.
Good luck with your project. Please do let us know how it's going.
Emma
gardenersworld.com team
