I have studied aikido and other martial arts in a variety of settings and with a variety of sensei. Some sensei lead a simple life and have almost no overhead; other sensei have a wife and kids to support, dojo rent to pay, etc. I treat them all the same, with a heart of humble gratitude. It really is not my business to tell them how to run their business, especially if their teaching is how they support their family.
But the original question was "How much does aikido cost?" I said I can't answer. There are similar questions that I can't answer, such as "How much does education cost?" "How much does family life cost?" "How much does living cost?" These questions may be good subjects for economics dissertations, complete with numerical models, but at another level they make as much sense as asking, "How much does the sunrise cost?" or "How much does the moon cost?" Some things just are; some "transactions" in life, like watching a sunset, are beyond the reach of economics.
If a martial artist feels he needs to sell various cool flashy stuff, even things like team clothing or after-school martial arts kindergarten, in order to care for his family, pay his rent or otherwise "keep the lights on" for training his advanced students, I don't see any problem. Even fine painters will paint portaits to pay the rent; fine musicians will play on corners to make some extra money (violin strings are not free). Many artists do commission work to pay the bills, including much of our fine "classical music" of the West and much art in museums. This commerical "compromise" does not diminish their art. Neither does the participation of a fine martial artist in various "retail" activities decrease my respect for them. The mere fact that I cannot afford the beautiful paintings of my artist friends does not in any way diminish my relationship with or my respect for them.
In any case, I'm glad you're happy with your present arrangments. Also, please don't call me Sensei on AikiWeb--I'm not a teacher of martial arts, only a student. But if we met on a Chinese street, you may call me Xian-Sheng; in that context it means nothing more that "Mister."
Peace to you,