Worked over 40 hours in one week and was asked to work Saturday's for 8 hours each. Was told to keep track of my hours. 28 hours worked on numerous Saturdays and turned in my hours and now learned that they are only going to pay me half. Is this legal??

Yes, as a salaried employee you have minimum hours spelled out at best. Are you a member of a labor union with a contract or straight salary?

Yes, as a salaried employee you have minimum hours spelled out at best. Are you a member of a labor union with a contract or straight salary?
Just straight salaried employee. I am a manager and my team worked the same. They said they were going to pay us straight pay and now they are changing their terms and now calling it a bonus...

That is a bit different. If they said they would pay and have changed their mind after you did the work it is a labor law violation. However, if you report this and seek compensation via the labor departments legal might there is always the chance that you will shoot yourself in the foot. Have you talked to anyone higher up than the folks who renigged on the pay?

First as a salaried person, ( assuming you are in the US) there is a min salary that has to be paid to be exempt from overtime.

But normally salaried people get nothing extra, if they work 30 hours of it they work 80 hours you get the same money.

The only issue I see is that they promised you a certain amount of money. But then they also said overtime, since you can't be paid overtime as a salary person that is a real labor issue.