Some freelancer sites let you list your service for sale, whereas on some freelancer sites, you will have to bid on the job and can work on the job when your bid is accepted. While bidding on jobs seem to be little easier than waiting for someone to buy your service, bidding on jobs also has a huge challenge. The competition is very big. Let's say an employer offers $100 for the job. Freelancer, in a hope to get accepted, bid for lower amount, and most of the time the one who bids lowest is hired.