For the Linear Algebra class that I'm taking currently, I needed a scientific non-graphing calculator. I quickly decided to take a look at what TI had in that category, and came upon the TI-36X series. Having read some reviews, I homed in on the TI-36X Pro.
The feature set of this calculator was described as "everything that the TI-84 can do, minus the graphs, for 1/4 the price," and I find that to be accurate. This little monster can handle polynomials, complex numbers, unit conversions, linear systems, regression, and lots more. It has everything I need in a scientific calculator, and I can always reach for my TI-86 when necessary.
All this in a sub-$20 bundle makes it a no-brainer if you need a non-graphing calculator. You can pick it up from Amazon using the referral link below, which supports this site. Thanks for reading!