You are correct... if you were to continue with a daily feeding schedule consisting of 200ish grams of flour, that would get expensive. I've gone as low as 25g/day, but have settled on 40g for the time being. Of course, remember that is coupled with an equal weight of flour for a 100% hydration level.
You will get different signs of activation depending on whether you are maintaining a liquid culture or a stiff culture. You will also develop a different flavor profile and acidity. It is fairly easy to convert from one to the other, so I believe it is merely personal preference. I no longer maintain a culture in the refrigerator since the one I had there was only part of an experiment to compare it to the constant-room-temp sample. I was curious how they would differ, and after several months, and not using the refrigerated version a single time, I discarded it. I found it to be overly acidic.
Every morning my culture is fed. If I am making pizza, I generally begin in the afternoon (for a next-day dough), so it allows perfectly for a few hours to pass from the feeding. If I am making bread, I begin my levain in the evening. I don't really worry a whole lot about the power in the culture because it is headed for a 12-17 hour fermentation anyway. Also, remember that now by making my levain it is in essence "feeding" the culture again.
I think you need to realize a little bit of culture goes a long way! Most home recipes are easily made with very small amounts of culture, and if for some reason you need an excessive amount, all you have to do is build a larger quantity. For example, take 25g starter, add 50g flour, 50g H20, ferment 3 hours. Take 50g of that, discard the rest, and again add equal parts flour and H20 and allow to ferment. Can you see where this is going? You can continue to build, discarding some each time, until you have the quantity you need. But, as I mentioned, you are generally going to be using small amounts.
The book I generally refer back to is Bread by Jeffrey Hamelman. He is one of America's foremost breadmakers, and was also a student of Prof. Calvel. His book gives excellent information on everything, but specifically contains some great detail about autolyse and culture maintenance. It is focused on bread, obviously, but I have found it provides a good basis to venture out. Technique, after all, is EVERYTHING. Give a man a fish and you feed him for a day. Teach a man to fish and you feed him for a lifetime.