sunflowers and bird seed
Sunflower seeds from bird seed can be planted in the garden if they have not been hulled or otherwise treated. You need the entire seed, including the outer shell. Planting from seed packets, on the other hand, will give you more options as to the type of sunflower--height, petal color, size of seed head, etc. (Also, the taller the variety, the more vegetation you'll likely have for fertilizer/compost.)