Beneficial plants?

[Daisy]

I'm glad to read the suggestions for live plants, a favorite when I had parakeets was a spider plant. For my finches I'm giving them romaine lettuce by placing the leaves vertically above their food dish until our weather improves then I will get them a spider plant to munch on. I have artificial plants with soft leaves for them to hop on and hide in but a spider plant should make their habitat complete. What seeds could I grow that would be inexpensive? Thanks