Short answer: Yes - I would do it again.
ML (Mid 2016): Cost-wise you may be able to gather the similar quality of materials for free, nothing are too unique and in many cases additional intensive research are still required. But, the Udacity provides nice structure and helps you to keep motivated.
SDC (2016): Much better experience for students, the quality of materials are higher, and amount of support from the peer group are extraordinary. Just one of the five projects in the first term are more complex than the whole ML nanodegree.
Haven't tried the AI nanodegree myself, but because it's a part of the new batch of programs I believe the experience would be quite positive (closer to SDC).
If you will decide to proceed with self-learning path, here is a nice multi-month study plan: https://github.com/ZuzooVn/machine-learning-for-software-eng...
In any case I strongly advice to take a look into Andrew Ng's coursera courses and Andrew Karpathy's CS231n on CNN (http://cs231n.stanford.edu/) as a supportive materials.
Also, if money is the main concern, you may want to apply to sponsorship, or maybe discuss this with your current employer.
Feel free to PM me on twitter (same nick) if you have any other questions, would be glad to assist.