I recently joined a 'local' (to Australia, lol) fish forum and bought some plant packs from other members who advertised.. I got in one pack approximately $150.00 worth of plants for $45.00. Thanks to just two such bargain packs, I will never have to buy plants again, and in fact my have to start rehoming some pretty soon if they all grow well, or my bettas will have no room to swim, lol.
Its very worth seeing what fishkeepers in your area may be selling when they trim their tanks up... I could -never- have afforded the amount and size of plants I got from these Aussie fishkeepers, if I was to buy them from a LFS.