What I think you ought to do is purchase some plants and try them out for a month. See if you can propagate them successfully without also growing algae. If you can then maybe purchase a second tank and go from there. But it's going to be a big investment.. you won't be able to get away on the cheap.. and amortization of your start-up costs is going to be over years, not months.
As with any beginner, I would recommend avoiding CO2 and high-light to start out, opting instead for easy-to-grow stem plants, mosses and rhizome plants (hygrophilia, ceratopteris, mosses, java ferns, anubias etc).
Growing submerged plants in direct sunlight is an invitation for algae so artificial light is preferred. 100 Watts of PC or T5 lighting over your 55 gallon will be enough to grow most of the plants mentioned.
I prefer to use test kits rather than dosing methods like EI (which of course I still follow in principle with dosing schedule and a weekly water change). If you go the kit route you'll need the following test kits: Nitrate, Phosphate, GH/KH and Iron.
And you will need the following dry ferts: Potassium Nitrate, Mono Potassium Phosphate, Potassium Sulfate, and Plantex CSM+B which, conveniently enough, you can buy these as a package deal here:
http://www.greenleafaquariums.com/aquarium-fertilizers-supplements/micro-macro-fertilizers.html
For a dechlorinator I would recommend Seachem Prime, but I honestly don't think it's necessary.
A filter is definitely not necessary in a fishless tank but good circulation is. That can easily be accomplished with some cheap powerheads.
I say good luck with this. There is a learning curve, but it is a lot of fun. :thumbsup:
-edit-
Oh I guess I didn't mention substrate. My favorite has always been Fluorite. It's got what plants crave.
