Almost like real white marigolds you can do it yourself from white toilet paper. For crafts, you need three-layer paper, floral wire (green, used by florists), twigs and a self-adhesive film. The whole process, which is not difficult to repeat, is shown in detail in the video.
The number of marigolds may depend on your perseverance, but having the skill to create flowers from toilet paper, you can easily make a huge bouquet.