One, find a studio that will allow you to do work study or volunteer or barter. Or make the appropriate changes in your living to bring the money that you need into your life. Actually BOTH would be good:-)
Therapeutics using Yoga require a certain eye, a certain understanding, a certain depth of training. There is a benefit to doing postures just as there can be a harm to doing them (when they are done in certain ways, certain durations, with certain intentions). Therefore the term therapeutic yoga does not refer to the benefits one receives when they go and take a generalized asana class. Benefit, yes. Therapeutic, not particularly.
When the student wants to correct a pattern they’ve built up in the physical body over time it is very unlikely that can be done while hurriedly moving from one posture to the next in a rush to I-don’t-know-where. The history of “speedy” asana practice is a history of occupying the furtive mind of adolescent boys. It is not a therapeutic practice just as Tai Bo or Step or 45 minutes on the eliptical are not. This does not mean there is no value to it or that it cannot serve a purpose and for some it clearly serves a deep and meaningful purpose. But again, it is not therapeutic.
The more a practice requires you to fit it (meaning the less it bends itself to you) the less likely it is to have profound therapeutic qualities across the board. Find a practice that can change to fit you. Find one that not only teaches alignment but one that also has compassion and an understanding that alignment precedes strengthening. Additionally you would be well served to find a place where the teachers are not dogmatic and are not asserting that one things fits every body.