It's not worth trying to do because any employer looking to sponsor low wage visa workers already plans to do so and will tender offers based on qualifications.
Because they will tender a low wage offer irrespective of your salary expectations, stating your willingness to take low wages will not be a deciding factor.
Most of the reluctance to sponsor workers is in the risks of sponsoring, not wages. Take your case, your goal is relocating not working for a particular employer. Nothing wrong with that, but it means someone who tenders you an offer is less likely to retain you. Or even have you show up because moving abroad is such a big change.
Advertising a willingness to work for less broadcasts your goal is to work abroad and not for a particular company. It can only hurt your prospects.
Good luck.
