Perhaps one of the more sensible alternatives to the Apple Pencil stylus for iPads is the SonarPen and it's now getting a second generation. The SonarPen 2's key selling point is its battery-free design and the support for some advanced features at a fraction of the Apple Pencil's price.
The SonarPen 2 is powered by a cable that you plug into the iPad's USB-C port, which is a bit of an inconvenience, but it's a pretty simple and straightforward solution. That's what makes it cheap and particularly useful for classrooms that use iPads, for example. You don't have to charge all the styluses nor do you have to pair them with the iPads.
In addition to the pressure sensitivity and palm rejection features, the SonarPen 2 brings tilt sensitivity, a shortcut button and a new pointy nib design for enhanced precision.
The SonarPen 2 can be paired with iPads from 2018 and later, while apps such as ibis Paint X, HiPaint, FlipaClip and others support the SonarPen 2 with all of its features. Other apps such as ZoomNotes, Zen Brush 2 and others still support the pen but with some features missing. SonarPen are in talks with other app developers too.
The asking price of the SonarPen 2 is HKD 245, which is less than $32, making it a much cheaper alternative to the Apple Pencil. Pre-orders are now open on Kickstarter.