Inexpensive algebraic programmable calculator

[Steve Simpkin]

I recently purchased a Sentry CA756 Graphing Calculator new in it's package at a thrift store for $7.  This model is commonly available at Amazon or Big Lots discount stores for under $20. As a graphing calculator it has a lot to be desired but as an algebraic programmable calculator, it is surprisingly capable. The following brief review from Mike Sebastion at rskey.org details most of the major features of this model.
http://www.rskey.org/~mwsebastian/review..._ca756.htm

It also features full alphanumeric text input prompts and output labels (12 characters max).  As far as program speed of execution, it's not too bad.  A simple addition loop program counts to 1,915 in 60 seconds. This is around the program execution speed of a HP-42S according to the following benchmark site.
http://www.wiki4hp.com/doku.php?id=benchmarks:addloop

The build quality and key press feel is comparable to sub $20 Sharp, TI and Casio advanced scientific calculators. Unlike those models, it does not feature textbook entry or more advanced functions such as integration, differentiation, summation or solvers.  But it does have reasonable programmability (400 characters), indirect variables (40), logic conversions/functions, fractions and primitive graphing functionality.  The 136 page instruction booklet is also reasonably well written, complete and easy to read.

Altogether it has a lot going for it for the price and may fill a niche if you need an inexpensive algebraic programmable calculator.