Dentures are made of acrylic and cannot be reheated in any way to try to reshape them. If you try to do that you will ruin them. A dentist will be able to correct your dentures so please do not boil or cook them.
However, I can suggest that you may want to look into getting a dental HMO insurance plan or even a dental discount plan. They both will help you with the cost of re lineament of your dentures. I noted a link below if you want to check it out