didnt have time to read anything but the title so i'm gonna give you the basics, pretty much east to grow plants and low light plants are always going to cost more than allmost anthing els. Your best bets are Anubius-low light plant that flowers a white tulip underwater and is also terristerial, its the heartiest plant you can ever get and comes in nano or large, barly any fish will eat it due to its sour taste, the only downside is it grows pretty slow and if you plant the risone under the gravle you can kill it. Next is ANY JAVA-this includes java frens and java moss, all are low light and grow great, the java moss is allmost impossible to kill once it establishes itself and is actually a neusence if you dont keep it trimmed, it will grasp onto anything you want including plants so be carfulle, the java ferns are great for a background covor, there is also a dwarf lace species that stays small. Only downside is the large java ferns seem to get a little bit of brown on the edges of the leaves and the also kind of look like a weed in your tank. Last is Bolbitus-This is a great low light low maintance plant, its a deep green lacey plant, grows really tall like the java fern and makes a good background covor, downside is that it grows kinda slow under low light. These are the best plants to start out with, once you get the hang of these you can move on up and eventually get a high light system to do all of those nice red and purple plants. Keep in mind that anything is possible all you need to do is go by trial and error. Good luck and PM me with any other questions.
~Zack~