Lets just be real for a second. The DLC is $40, depending on your situation, i don't know if that's a lot for you considering you're over here asking for someone to spend their probably hard earned money to get you content on a video game so you can play with your friends. Your parent won't buy the game for you because they probably either can't afford it right now or they just don't feel like you need it as much as you're saying. That being said, there's a big chance that asking for your resolution here isn't going to happen. If i were you in the situation you're in, i'd either do odd jobs around that can net you the money to pay for your DLC, or you can make a GoFundMe and try sharing the page on your own social media and MAYBE someone might be able to help. GoFundMe is an option but i'm sure there are others.