Also, for the plants, $10 is reasonable.
Just have to buy some flourish comprehensive.
What kind of gravel do you have? Hopefully it's not too large or two small.
I have a livebearer tank with no ferts whatsoever, and just 6500k lighting.
The plants that are surviving are:
Water Wisteria (doing OK)
Vallis (doing OK)
If you wanted to go true south american, I would look for swords. (biotopes are typically more expensive, but for about $13 shipped, you could get:
1ea.- Echinodorus Cordifolius (Radican) SM
1ea.- Echinodorus Bleheri (Amazon Sword) SM
1ea.- Cabomba Caroliniana (Cabomba, Green)
1ea.- Proserpinaca Palustris
1ea.- Ludwigia Natans (Ludwigia Repens)
They're also nice enough to where if you wanted a smaller quantity of the "bunch plants" they could charge you less... Something like, if you wanted 4 stems each instead of 6-8 you could save a few dollars.