Ekta,
Freelance Writing Center is not a scam. I have written over 160 projects (800-100 pages), and over 100 blogs (300-500 pages) for this website in 2008. I can prove this through saved work and PayPal payments. When I request payments, I receive them within a few hours. At times, when it's very busy, it takes a day or two. Most of the time, I'm content with the payment process.

As a Public Admin graduate student, and a past UCSB graduate in Film & Media Studies, I am a very diverse writer. Freelance Writing Center only require tests to ensure you have good writing skills. You have to also write an essay about plagiarism.
I can ensure you that you will make money writing, but you will need to really be serious. Deadlines are extremely important, as the site and clients depend on you. Since I have been paid good money for writing, the only drawback is the amount of time it takes to produce the projects because there are some customers that submit assignments, which requires double the work.
Overall, I have done well writing for the site. This is a good second job. In order to make a living writing here, you will need to exhaust a great deal of time. You have to take into account the time it takes to conduct the research. I have an extensive library of books ranging from Public Policy, Film, Communications, Business, Public Relations, and Government. I also have access to library articles. I might add, you should obtain log in access to JCOST. Google Scholar has been very useful for me.
I have written quality papers in APA and MLA. I usually avoid Chicago, Harvard or Turabian, as they require additional time. Remember, time is money. I learned that after many sleepless nights at the computer. You have to enjoy writing, or you will dread producing projects. I have planned to write for film for the past decade and a half, but the Writer's Strike, and the economy have put that goal on hold. Although I produce client projects, it allows me to maintain deadlines, communicate, and endure high volume work.
If you think of writing as a business, you will succeed. Be direct, responsible, and professional. There are some clients that can be rude, and others are demanding. The majority of the clients are understanding, and helpful. It doesn't matter how good the quality your work is; if you're late, clients will be rude. Within the last 15 months of working for the company, deadlines tend to overshadow anything else. I have written some great papers, but people gave me poor feedbacks for missing their deadline by a few minutes. Communication is the key to success. Out of 160 projects, I have only experienced a couple bouts with my quality since I picked up projects outside of my expertise like Chemical Engineering. Stay within your skill level.
Only pick up projects you're capable of writing. Don't fall into the trap of picking up ones that seem interesting because you will struggle in the end. This past December, I picked up over a 100 pages (15-20 projects) during finals week. I had my own finals to complete for graduate school, as well as other projects. I had to travel up North, and drove in the snow to visit my family. I endured a high level of stress putting myself through those unpredictable moments. When I left my work area, it was hard to find credible sources in the local libraries.
Luckily, I have a quality Apple computer, and one of those ATT USB 3G Internet sticks. Freelance Writing Center is the only site that I have made money writing for. Other sites like Helium, and Shvoong were a disaster. Freelance Writing Center is a credible site. I have proofs that I made money writing for the site, and that I have a high level of experience writing quality papers.
When you writing on a daily basis, the words just flow. I don't need to look at my Writer's Manual too often because I have complete confidence in APA and MLA citing guidelines. Writing papers for clients range from scholarships, student assignment, research papers, essays, admission essays, employment essays, and a wide range of other work. Academic writing helped me maintain deadlines, writing volume, knowledge, and kept me within my ultimate goal of writing for film.
In retrospect, stay within your skill level. Don't pick up too much, especially if you have your own work to complete. If you don't complete the work, nobody else will. Ultimately, the student will fail the course, and possibly, it could be their last assignment to graduate.
Expand your citing skills. Communicate with your clients about any problems, concerns, and questions you have regarding their project. Make sure you communicate with the company when they send messages. I would recommend using PayPal to accept payments. It's quick and efficient. Get one of those PayPal Debit Mastercards too. You can take out money at any local grocery store - just make a purchase, and punch your Pin number ($400 a day limit). Some grocery store also limit it to $200 per day. Won't cost you a fee.
As for writing, be confident, be responsible, be professional, be courteous, don't get worked up when clients are rude, keep within the page requirements (I tend to overwrite), use credible sources (Google Scholar, books, articles, and etc.), Limit using too many quotes, and develop paraphrasing skills. After receiving good feedbacks, ask for a raise for your per page rate. The last minute projects that are due within 8 hours or less pay high rates. If you pick those up, make sure you complete them. Deadlines and quality work in unison, but I can vouch that deadlines are more important to clients than quality. I don't like to reduce my quality because of a deadline. A client may complain about quality. It's a Catch 22. Some clients don't like to communicate.
Think of working on this site like serving customers in a restaurant. Give the customer everything they want, communicate with them during the dining experience, and stay professional - even if they're unbearable to deal with. If you follow these steps, you can make some good money writing (second job). Don't rely on this as a primary form of income unless you plan to be married to your computer. If you can write quick, and efficient, then you can use this as a primary job. Write as if it were your own work. You receive a good sense of satisfaction when client praise your work. In a way, you're a part of their future. Without you, they probably wouldn't graduate, or pass a course. It can cost them money to take the course again.
After writing for the site, maybe you can gain skills to write a book. the volume of writing, and deadlines helps one achieve discipline. Anything that involves online writing requires discipline. Best of luck to you. Happy writing!