The hardest part is figuring out how much to charge, whether to charge an hourly rate or a day rate and how to make sure you're getting what you deserve. And what you want.
You don't get benefits and have to cover most, if not all, of your own costs, so factor that in your rate.
Also, remember as a freelancers, you can write off supplies, Internet service, transportation, your home office, your cell phone bill, and a slew of other freelance-work related expenses.
Here are a few articles that will help set you on your way. I surely don't know the right answer and would hate to give you a number and then undersell you or lead you to overbid and lose a job.
A quick reference I read once was to shift the decimal 3 places in your yearly salary and cut it in half. So if a junior makes between 35-50K annually (depending on several factors, read: "How Much Am I Worth?") That means you'd be charging anywhere from $15 - 25 an hour.
Don't take my word as scripture though. Do some research, ask around and most importantly, do what's best for you.
How To Determine Your Freelance Rate
A Beginner's Guide to Setting Your Freelance Rates and Fees
Nine Factors to Consider When Determining Your Price
Setting Your Freelance Rate in Advertising
Freelance Switch Hourly Rate Calculator
