It's difficult to suggest about the journals without knowing the quality / technology used in the works. However, all most all of the journals from "Elsevier Publishing Group" are charge free. Here, you will get many good journals of high quality. Please see the impact factor, 5-year impact factor of each journal from their website. Higher impacts apparently considered as higher values.
Even if some journal requires processing charges, you can contact with the editors for possible exemptions of the fees for "Low income countries". If they have any plan like this then you will get informed about this.