COVID-19 contributed to the largest student performance decline in mathematics since 1990. The nation needs cost-effective mathematic interventions to address this drop and improve students' mathematics performance. This study presents a cost-effectiveness analysis (CEA) of three algebraic technological applications, across four conditions: "From Here to There" (FH2T), Dragon Box 12+ (DragonBox), Immediate Feedback and Active Control. This CEA study uses impact measures from a student-level randomized control trial comparing student learning from the three treatment conditions to the Active Control condition with an analytic sample of 1,850 middle school students across 9 schools, 34 teachers, and 127 classes. The results from the CEA indicate FH2T costs $39 per student and produces an average effect of 0.135 on algebraic achievement resulting in a cost-effectiveness ratio of $291. DragonBox costs $55 per student and produces an average effect of 0.269 on algebraic achievement resulting in a cost-effectiveness ratio of $206. Overall, the current CEA study demonstrates the efficiency of FH2T and DragonBox as low-cost interventions for improving students' algebraic performance and addressing the nation's decline in mathematics. [This is the online version of article published in "Journal of Research on Educational Effectiveness."]