very low quality bid making market down

I saw several bidder is bidding just like free for any client making it very hard for calculating actual project cost. Is it not lose for both scriptlance or serious bidders? The job which can not be done less than 100$, freelancers posting only 10$ ????????????? How can it be possible?
My suggestion:
1. Hide bid amount for each project
2. Make budget mandatory for all fixed projects.
3. Should have something which will stop employer to get service almost free of cost or being cheated.