You can easily multiply a spider plant (Chlorophytum comosum), as well as other indoor plants that produce long trailing runners such as strawberry begonia (Saxifraga stolonifera), Boston fern (Nephrolepis exaltata), episcia (Episcia spp.), rosary vine (Ceropegia woodii), and apostle plant or walking iris (Neomarica spp.).
Just place a small pot filled with potting soil near the mother plant and fix it one of the babies onto it with hairpin. Whenever the soil in the small pot is almost dry, water it. In a few weeks, when you can see a few roots through the drainage hole, you can free the baby by cutting off the stolon. It is now an independent plant that you can place as you please in your indoor decor.