We work over the finite field F-q. We introduce a notion of unstable P-algebra over an operad P. We show that the unstable P-algebra freely generated by an unstable module is itself a free P-algebra under suitable conditions. We introduce a family of 'q-level' operads which allows us to identify unstable modules studied by Brown-Gitler, Miller and Carlsson in terms of free unstable q-level algebras.