The company ive done mystery shopping for you dont need an ABN and youre not employed by them. You are classed as a supplier. You need to sign a form saying you are a supplier and are not being taxed. I declared it at tax time as an income but if youre a SAHM and dont have any other employment, you shouldnt have to pay tax on it as i doubt youll go over the threshold with it. As for Family Assistance, being you are a supplier and the income is tax free, you dont have to let them know.