What are /r/mspaintbattles' favorite Products & Services?

From 3.5 billion Reddit comments

Personally I took the class in high school so the teacher taught us most of the stuff but I think Professor Messer should be very useful tool for you. The teacher also bought a software called Pass4Sure that had most of the questions that were on the exam but that is quite pricey.

There's phone versions of paint.

In fact they're worse than paint, therefore better.

https://play.google.com/store/apps/details?id=com.adsk.sketchbook

https://play.google.com/store/apps/details?id=com.pcvirt.ImageEditor