If you're unfamiliar with P2P sites, they are audition services that charge voice actors a yearly fee to submit auditions for commercials and all genres of voiceover work. They can be an excellent tool to get several clients but newcomers tend to skip the coaching process and sign up for P2P sites in hopes of making a living doing voiceovers. Is it possible? Hell yes! Anything is possible but if you're not skillful in delivering professional performances, you will have an arduous time booking work.
Professional demos are also a must when you're on a P2P site or just marketing from your own personal website. A professional presentation is a must if you want to be taken seriously and book work. Even on P2P sites, I see talents with no demos who add minimal information on their P2P site profile. While I understand the mindset of cutting corners, I can't stress enough