I am planning on quitting my job. They reduced my hours to 10 a week after promising me full time and I can no longer afford to pay rent. Therefore, as soon as I get hired at a new job I will be quitting immediately with little notice because I need an income ASAP or risk eviction.(I don't want to put in my 2 weeks without a job lined up AND I'm in an at-will state so they could let me go whenever they want if I tell them I'm looking for another job)

I looked in my employee handbook, which was just given to me 2 days ago (after 6 months employment) And they stated that if an employee fails to give 2 weeks notice, their last paycheck will be paid out at minimum wage.

Is this legal? I know an employer can't change the wage for hours that you've already worked, but they're allowed to give you notice of a wage reduction going forward. Does this count as prior notice? Or because I already worked the hours they're not allowed to reduce it to minimum wage?

I live and work in Wisconsin.