Probably, I don't really see 20% as something too much when it comes to freelancing. As long as you are able to make reasonable amount of money, you are making 80% of the total money which is quite cool.Most of the freelancing site take only 20 percent of the job fees and this is not much considering the work they do. They need money to run the site. And there are that collect money from client to pay you. Do you know it cost them money to sent your payment to you? To me, 20 percent is not much. But if you sites that don't take much, then you can try pro blogger, linkedin and other site that connect you with client.