Issue with parents and replacing a part of a car, help?

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Hi, about a week ago I hit my dad's car with my mom's car while backing out. I managed to break the tail light covering in the process. (sorry im not good with car parts) But anyway, my mom insisted that I replace it with a new part (not a used part). The part cost me about $90. I didn't mind that too much, I guess I had that coming, but when I recieved the part, which I had requested just be the tail light cover and lense (no light bulbs or wires), it came with light bulbs. I looked up the price of just the lightbulbs and they added up to about $20 to $30. My dad insisted that the new lightbulbs be kept inside the tail light lense instead of the old ones, and he doesn't really care that I was cheated out of $20, by both Autozone (don't ever shop there) and my dad. The used lightbulbs that my dad gave to me are about 4-5 years old, and have maybe a year's life left in them. This means that my dad would have to get new light bulbs for a more expensive price. I feel that he sees this as an opprotunity to cheat off a minor, with no legal rights of his own. I need help. Should I fight him on this? Is there anything I can do legal wise? He's managed to steal a $50 Best Buy (I recomend shopping there) gift card from me as well, should I believe that he does this intentionally? Should I just let him have the lights, or should I get my deserved money? Am I giving a rational arguement, or am I being dumb? Help me out, Yahooers, should I just swap the light bulbs out while he's not looking? Should I pester him until he caves in? Give me some advice please, and whoever manages to convince me the best will get 10 points.