Price: Under $30 (I bought mine from Amazon) And here is a link from officemax for $22.99:
TI-36X Pro Scientific Calculator 36PRO/1L1/A (Google Affiliate Ad)
Review: The TI-36X PRO is a calculator which seems to be designed specifically for standardized testing. Basically, it takes most of the features of an advanced graphing calculator, such as a TI-89, and puts them in a package that is allowed on your standardized test. I bought this calculator for the FE Exam and I as amazed at how much it could do.
Solver: One of the most powerful features is the numerical solver. You can enter any single variable equation and solve for the variable (a numerical result). This comes is so handy on a test where you are provided a formula and the variable you need to solve for is not isolated. You have to be a little careful, though. The numerical solver only returns one solution, even though if the equation you entered has multiple solutions, and there is no warning. The polynomial solver, on the other hand, does return all possible solutions. Obviously, the equation must be in the form of a polynomial to use this feature but usually that is not a problem. As if that wasn’t enough, there is also a system solver. This can be used when you have a 2x2 or 3x3 linear system of equations. This feature is somewhat duplicative since you can also just transform a representative matrix into reduced row echelon form (rref) on the matrix menu, but oh well.