How many p's for beans

I absolutely love broad beans but never have the greatest success growing them for myself.  So for a treat l decided to buy some.  I was in Sainsbury's (promise this is not advertising!!) and bought a packet of 500g of shell on beans which cost me £1.50... l came home planning on making a lovely salad with them and some home grown runner beans and mange tout (first picking of lovely young pods) l do enjoy podding broads.. and counted 15 pods to be popped open to retrieve the beans.. (that is 10p a pod) and weighed the end product... 155 grams.. that is approximately 1p / gram.  lntrigued l counted how many beans (60) which is around 2.5p/bean or £10 a kilo... 
Sometimes my brain goes off on a mad mathematical tangent.. and seemingly beans got its attention today!!  I am going to enjoy my 30 beans tonight.. but wonder if the farmers are making a killing or not... thoughts?