The designs, format and weighting are different, but the skills being tested are the same.
I would recommend taking the same preparatory program as the test you intend, especially if you are unused to language proficiency tests, because much of the success in test-taking comes from being familiar and comfortable with the test format.
On the other hand, if an IELTS program is inexpensive and convenient for you now, why not take it, just for the experience of a language proficiency test? Many of the strategies of reading and selecting answers will be the same.
Otherwise, I would wait a while until you can take a TOEFL preparatory course-- don't wait too long, though!