✔ 最佳答案
my experience:
first learn with free e-learning materials. RTHK's is very good. Go take a look:
http://www.rthk.org.hk/elearning/GoGoJapan/map.htm
after finishing the RTHK's free courses (there are 2, by the way) which takes about 3 months and is sure that your strong interest in Japanese is still there (^v^), start learning with the following course materials:
<< 大家的日本語 >> 初級I : textbook ($93), a set of 4 CDs ($267), 文法解說書 (初級I & II) ($53)
I spent 3 months on e-learning because:
1) it helped when I learned with << 大家的日本語 >> in which the whole book, except for some vocabularies, is in Japanese.
2) if I lost interest in the first 3 months, I got nothing to lose. I didn't have to regret spending hundreds of dollars on books and CDs which I still had to think about giving away or putting them in the back of some drawer.