In almost all cases, a personal injury lawyer will work on a contingency basis. This means that the client only pays attorney fees if the client collects money from the case. In cases where the client loses (does not collect any money), then the lawyer would not collect any fees. In the infrequent situation where a case will go to trial, it is possible that the lawyer will expect the client to pay the cost of filing the case at court. It is always a good idea to clarify any fees and costs with your lawyer as there may be some variation from lawyer to lawyer in these issues.
Contingency fees for personal injury lawyers will vary from state to state but the typical range is between 33% and 40% of the final award. In some situations, an attorney may be willing to negotiate a smaller percentage for large cases, so it never hurts to ask. Be advised, though, that you should not select a lawyer based on a willingness to reduce their fee - as a larger award will typically more than make up for a modest difference in contingency fees.