First of all, you need to be very clear and define your project in detail before hiring freelancers to save time and avoid frustration. Make a summary for the description that you’ll share with freelancers. This will save you a lot of time (and frustration).
Have all the prerequisites ready for the job: if you want a website, remember to first hire a designer to have the logos and typography, and only after hiring a designer, you hire a developer.
With that in mind, you have to be crystal clear on the budget and type of professional you want. Some prefer fixed prices, but usually most prefer being paid by the hour. Do some research to find the right hourly price, or, in case they prefer a fixed price, research it as well and find the budget you’re willing to pay them.