Assertion: subscriptions are better, but people generally don't like them.
Consider the iTunes music store, unlike Yahoo music or Napster they offer a very simple fixed price of $1 per song. Whatever you buy is yours to keep. All other online music stores offer a subscription based plan where you pay $5 - $10 per month and download as much as you like, or some hybrid scheme.
One might thing that the subscription model is more popular. After all, it's better value, just think: unlimited songs!
Wrong! Even people that buy more than 10 songs per month prefer the simple iTunes buy-once model. People like to feel in control. People also like to any kind of commitment. Finally, people don't want things to be too complicated. Keep it simple!
Subscription services do sell in some scenarios. Take online role-playing games (please!): something like Sony's Everquest charges $40 for the game and then another $15 per month on top of that, yet is hugely popular. Some players spend hundreds of hours online, fighting monsters, completing quests, building up their virtual character, earning fake money (even more fake than the so-called real money) and so on. Everquest is designed to hook people into "just one more quest" and keep them playing and paying for-"ever". It works, too: Sony was astonished at how much money they made off Everquest.
Some smart new online games (most notably Guild Wars) have figured out that they can reach a much larger market (and more money) by not charging a subscription fee. Instead they'll release an "expansion pack" every few months and steal people's money that way.
Yoga teachers are notoriously bad at business. Most yoga classes I see advertised around the University want people to sign up for a 10-session course, or something of the sort. Most people I've talked to don't want to make that commitment and therefore end up not doing any yoga at all. Major untapped potential!
These yoga courses mean well, of course. People won't get any real benefit from just a single yoga session here and there. If someone really wants to improve their bodily and mental condition, it is best if they do two 90-minute sessions per week. But, low and behold, no one wants to do that. People don't care about themselves.
The same hold true with chanting the maha-mantra. Great if someone utters the mantra once. However, Krishna is most pleased when we make a commitment to chant a fixed amount each day. When Krishna is pleased we automatically also get satisfied. It's like watering the root of a tree. Again, the subscription model benefits all parties. And yet again, few people want to make the commitment.
Solution: I plan to offer a 40-minute yoga class once a week for a one-off one pound fee/donation and then follow that with some (free) chanting and philosophy, for those that are so inclined.
Scheme: attract people with something that they think they want, though it won't really benefit them and then make it as easy as possible for them to take to something that actually will give unlimited benefit.