Bonding or Crown

I have a dentist that insists that I need to have a crown for two teeth. I have little to no money for crowns but he insists that bonding would not be helpful and that I would have to have crowns. I already got two crowns from the same dentist. One which food always gets stuck under even though he said it should help my problem with food getting stuck between the teeth in the upper left section of my mouth. Right now due to having a broken tooth on my upper right by on crown and a broken tooth on my lower left side under the other crown my teeth near are wearing away slowly. What would you suggest? I cannot really afford new crowns for awhile even with insurance. I wear a guard on my lower teeth in the evening when I sleep because I do not feel comfortable with it during the day. I tend to want to chew on it too much and suffer from TMJ.