What is Reddit's opinion of Texas Instruments TI-30XS MultiView Scientific Calculator?
From 3.5 billion Reddit comments

By popularity on Reddit, this product is:

1 review of this product found across Reddit:

This is my favorite calculator [1]. It is a TI, but non-graphing, and only $20. What I've always told people is that if you can't do it on this calculator, then you should be using a computer. You should be able to do simple graphs by hand, or at least know how to do 2d shadows of your object. I've never needed an 84 or 89 in my entire life, having a physics degree.

There are also TI emulators that you can get on your phone. I have an 89 on my phone[2]

[1] https://smile.amazon.com/Texas-Instruments-MultiView-Scientific-Calculator/dp/B000SSLBRK/ref=sr_1_3?s=electronics&ie=UTF8&qid=1514006508&sr=1-3&keywords=ti+30xs

[2] https://education.ti.com/en/software/details/en/6633925F6176419197BF6CA051F5F7B4/89ti89tioperatingsystem