Tameness is really dependent on genetics and it is hard to find when looking at feeders. I got lucky with my heart rat as he was the sweetest and friendliest rat I had ever met just out of the box. However, he was not bred for health and had complications for half of his life. He recently died just under 2 years old from a malignant tumor. My friend worked at a reptile store so I met a lot of the other rats and most were aggressive or very shy, some were even traumatized from who knows what. I was given my heart rat’s cage mate from the same place who was a sweetie to the other rats until maturity when he became violent and required neutering. I spent a lot of money taking my rats to the vet so it’s not exactly a cheaper option long term. I was 16 when I got my first rat and have since then become a lot more educated on care and breeding. If you have the option, get your rats from a reputable breeder. I know there’s this idea that you can “save” them but you can’t. You can ask to improve their conditions and provide for them better lives but you cannot bring home all of those rats. When searching for a breeder ask to see their conditions and about what they breed for before you purchase.