I loved Amazon Prime and was a member for several years until they boosted up the price. I wasn't working at the time so I just let it go. If they let you pay by month that might be easier.
It was definitely worth it for me though. I live at least 30 minutes from any big store so any time I needed a birthday gift or whatever, all I did was order it on Amazon rather than making a special trip to get it wasting my time and gas money.
For years I did most of my Christmas shopping with Amazon Prime and that was very helpful especially with their lightning deals they have going on that time of year.
Another bonus was being able to stream movies and tv shows, Prime membership offers many of the same titles you would get using Netflix or Hulu Plus, at no extra cost. And being able to order new releases was great too. Maybe a bit more expensive but saved me a trip to the redbox!
Another great thing about it was that I let my other family members use it as well. So not only were they able to take advantage of free two day shipping, but I could always be sneaky and look to see if they bought me any presents!
Now my sister has it so I just use her account.