One of the great things about plants, especially stem plants is the ability to easily propagate them (create new plants from the cuttings).
Stem plants are very common in the aquarium and very easy to multiply. Where some plants have runners that run off and sprout a new plant automatically, most stem plants you can simply snip and replant. Stem plants often grow too large for the tank and can look unsightly.
Stem plants either start dropping back into the water or can stick out from the top. So they are simply trimmed. Once you snip the stem, you can replant the part you snipped off. Just plant it back into the substrate.
You can easily buy a small bunch, and slowly over time, end up with a tank full. We do this by propagating them.
Some stem plants will have roots coming out from various heights of the stems, just below this area is usually the best place to cut it from, so the piece you cut off already has its own roots. We then replant the bit that we snipped off.
Be careful not to snip it too low, as the one we leave in the substrate wont grow back if it has no leaves. I tend to cut mine just above half way, and then plant the new one. Over time the new, and the old plant grows back so you end up with two from one.
We can do this with most plants, Anubias for example you just need to cut the Rhizome (the thick length where the leaves grow out from) and replant. However most stem plants are by far the easiest.
If you have the patience you can buy a couple of these type of plants and slowly end up with a tank full.