How to convince my parents getting me two rats?

I had a dog once when I was 8 and when it died my parents said no more pets. But I really wanted rats so I showed them how much I wanted them I did the research and I showed it to them and I made them take me to the pet store and I showed them what wonderful pets they are. And you are right rat cage cost around 70$ and it comes with food and toys, rat 6$ a piece.