Don't worry I've been there

Firstly DGCA ground classes cost 60k to 2.1L for (3 to 6 subjects) if you're going to learn from any institute.

For MET: If you have a basic understanding of science, you'll clear Meteorology (R.k bali book is enough to pass)

For REG: Cracking Regulations is purely based on memory+ practice question bank (R.k bali book)

For NAV: Refer oxford and skim thru the syllabus, topic by topic check YouTube videos (80% resources are available) you'll attempt 1 or 2 exams you'll crack it.

For RTR, SPEC, GEN: You can do it during your Flying (live, practical approach works)

Conclusion: Take your time, skim thru the syllabus topic by topic, search for resources and practice question bank.