With my playing time cut down due to school, im hardly making any money. One way I can make money over the week is herbs, but im not sure if they will survive if i leave them all week. Even if i use supercompost, I dont know if the herbs can still die after they are fully grown

They won't die after they've fully grown :) Once they're grown they're done and they'll stay that way until you harvest them.

If you are worried about losing money from herbs dying, do note that it's still very good money even if you average a death every other run (which is pretty much the average).

 

With this in mind, ranarrs are 130k/run assuming you have scroll of life.