Algebra is all around us!
I use algebra almost everyday as an Engineer. However, even those who do not choose a STEM career will still use algebra when looking at their paychecks and even calculating ways to purchase & maintain your first car.
Taxes and other deductions removed from your paycheck are typically based on a fixed percentage. You can calculate how much your actual take home pay will be using algebra, the number of hours you plan to work, and the percentages (%) used in the deductions.
One can even use algebra to determine how much they might spend on gas having the average miles traveled monthly as variable "m" and the general miles per gallon value your desired vehicle achieves.
In high school and college I used algebra after spring break to estimate what grade I would have to earn on a final exam or big project in order to get at least an 88% overall in the class. The weighted averages teachers provide on the syllabus, your current test/quiz/homework grades, and algebra (e.g., solving what grade on project is needed to have an overall grade of 90, where overall grade(x) = 0.4*project(y) +0.1*participation+0.3*tests+0.2*homework; & all other averages are available) are keys to strategies as well.