Earlier quoted context omitted.
I use them pretty regularly, since I discontinued my Amazon Prime membership. Amazon without Prime is a shipping fee quagmire. Jet is terrible for ordering books, but other than that they are pretty prompt on delivering stuff within 2 days. You get discount for using debit card (1.5%) and using a larger cart drops prices(which stops after you added a bunch of items).
Amazon also gives you free shipping once you spend above $49. And if you have a business account you get two day shipping as well at the same threshold.
I have never ordered enough from amazon to make prime worth considering. The troubles I've had lately mean I just assume Amazon won't ship in time and so once I see something on amazon that I think I want I look to see who else sells it. I'll pay $.50 extra to have it shipped the next day.