Texas Instruments models have been typically used for high schools and universities since the late 1990s. The TI84 model was first introduced in 2004. However, the price has not seen much decline over that period (as would be expected with most technological products). With new technologies appearing more frequently, any decision to use expensive equipment must be approached very carefully.
Even so, the TI83 and TI84 models are highly applicable to the 10, 20, and 30 levels of each pathway in Saskatchewan Mathematics curricula. If physical units are available to all students, they can be a great resource. Otherwise, alternatives should be considered, as in the chart below:
Digital Graphing Calculators Search terms: graphing, calculator, graph, function, online 
Link  Description 
Search terms: ti83, ti84 emulator, simulated, virtual

Virtual TI83 calculator emulator

Search terms: desmos, graphing, calculator 
Desmos online graphing calculator

(This list is representative. It is neither an exhaustive list nor a deliberately curated list.)
Digital Statistics Calculators (ie: zscores and standard deviation, for Math Foundations 20) Search terms: online, stats, calculator, statistics, deviation 
Link  Description 
Statistics Calculator 

Meta Calculator 

Free Online Statistics Calculators 

(This list is representative. It is neither an exhaustive list nor a deliberately curated list.)
Digital Finance Calculators (ie: future value and present value of compound interest, for Math Foundations 30) Search terms: online, financial, calculator, tvm, time value of money, solve 
Link  Description 
Finance Calculator  For finance (ie: future value and present value of compound interest, for Math Foundations 30) 
Financial web Calculator  HVKS.com has a similar webtool 
TVM Calculator [Ultimate Financial Calculator]  FinancialCalculators.com also has a TVM (time value of money) calculator 
(This list is representative. It is neither an exhaustive list nor a deliberately curated list.)
Regression Analysis: (ie: bestfit line or curve, for Math Foundations 30) Search terms: regression, calculator, online, linear / quadratic / exponential / logarithmic / sinusoidal, webbased 
Link  Description 
Quadratic Regression  Desmos can do regression analysis, but some coding is required. Search for an existing work made available to the public. 
Regression Calculator  WolframAlpha has a calculator widget that handles all regression types 
GraphPad QuickCalcs: linear regression calculator  Graphpad has a linear regression webtool. 
Linear Regression Calculator  Goodcalculators has linear and quadratic regression webtools. 
Quadratic Regression Calculator 
(This list is representative. It is neither an exhaustive list nor a deliberately curated list.)
A Note on the Use of Calculators in the Classroom
Teachers have mixed opinions on the use of calculators in the math classroom. Calculators can be a valuable tool allowing students to work more quickly and focus on bigger ideas, but can also reduce the need for efficient mental math skills.
Access to calculators does not negate the need for students to develop paperandpencil and mental methods. Rather, when used appropriately, calculators play a key role in developing students’ fluency with numbers and operations and estimation skills. (NCTM (2020) 
When teachers choose to integrate calculators into the classroom it is important that they are selective and strategic in their use. The NCTM has published a balanced position paper: Calculator Use in Elementary Grades – National Council of Teachers of Mathematics^{1 }on the use of calculators in the classroom. 
At the end of the day, teachers should consider deeply how the use of calculators will propel student learning and consult with their school administrators and division math contacts regarding expectations for calculator use in the classroom.