This depends. If the graphic designer works in a corporation then they get paid by salary. Many corporations have graphic designers in their marketing team. Freelancers can decide how they get paid. It is recommended that it is per product phase completion. (IE if you are designing a logo, you should be paid not for just completely one logo but for showing low-fi mock-ups that the customer would then give feedback on then pay you for the next phase). Your hourly rate should be considered in each project phase.
As a beginning designer working at a company that offers a full-time, 40 hour a week job, you can expect a starting salary somewhere in the $35K-$40K. This number could very different though, depending on the size of the company and the region you’re located. Smaller companies and smaller communities tend to pay less.