Basic question about kerosene?

I am looking at a kerosene heater that uses K1. I know that you can buy plastic containers of clear kerosene at WalMart, but they are like 8 dollars a gallon. The stuff you pump at a gas station that sells kerosene is under 3 dollars a gallon but it is red. Is the red just a dye or is it lesser quality than the expensive clear stuff? Also, is number 2 heating oil just a less pure kerosene or is it entirely different? Same question with diesel fuel- is it all the same stuff or completely different?