Hello I am thinking of getting iPad for the free Airpods. But I was wondering if there are also more affordable/ cheapest/promotion options? Any suggestions are welcome!?

Buy under Apple Education for students to enjoy cheaper rates heh

If you're in it mainly for the AirPods, it sounds like some of the other things you've listed could be achieved for a lot less, especially since you've mentioned it's mostly light use. For instance, your phone can be pretty handy for note-taking/reading ebooks on the go, and a drawing tablet (like this one, which can be used with a free drawing software like Sketchbook) will set you back less than $100, and should do the trick for illustration/colouring. This way, you could buy AirPods Pro and still have money to spare.

Of course, this approach involves some minor compromises on convenience and the power of your tech, but in the interest of financial prudence, it might be an approach worth considering. Good luck! :)