Grab some seedling trays or plant pots or whatever containers you can find. Mitre 10 and Bunnings have recycle bins in the garden section where they can be picked up for free. Nelmac Nursery by Whakatu Marae also has a free plant pot bin, as does Restore.
Fill the seedling pots with potting compost (normally a mixture of compost and sand/pumice to allow water to drain through). Potting mixture can be made pretty cheaply if you mix your own but if the cost is a barrier, let us know and we'll help source some.
If you don't have the room to plant all the seeds, perhaps give some to your neighbours/friends to plant.
Plant your seeds at a depth of approximately three times the diameter of the seed. Place them in a warm sunny location and water as needed.