Ludwigia Repens is a fairly common stem plant in the aquarium trade. With the right conditions, these leaves can produce a very stunning red color. They grow well in all types of conditions, in my experience, but less light means less red with these. The addition of CO2 and good lighting will bring the best colors out, but it is not required.
This Ludwigia Repens is already converted to its submersed form, and is currently being grown in low tech conditions; no additional CO2 or fertilizers, and standard lighting.
Price is per stem. To replant, simply remove any leaves that may be buried and stick into substrate. They do no require the use of root tabs, and feed from the water column.