No, there's no educational discount on Adobe Stock. However, if you’re a student, teacher or anyone working in education, then you can get a big discount on an All Apps Creative Cloud plan.
This means the price of the Creative Cloud plummets just $19.99 / £16.24 / AU$21.99 per month for the first year, and then (if you decide to continue) $29.99 / £24.96 / AU$43.99 the following year.