I can't tell from your questions which jurisdiction your case belongs to. I am based in Ontario, Canada where you will indeed find firms that will work on a contingency fee model. Class action lawsuits are increasingly funded by third parties as well, who will bear the risk and receive a percentage upon success. In Ontario, you can even apply for funding from Law Foundation of Ontario. I encourage you to talk to a few firms in your area. I am sure you will find a workable model with a law firm as long as the case has reasonable chances of success.