M'lud is correct to question whether we are being fooled into paying too much for bait companies 'special, selected, will catch everything, unique flavoured...blah, blah, sweetcorn'. Utter goolies.
Cheap supermarket sweetcorn is just as good. I buy ASDA Smartprice (no preference with supermarkets - ASDA is just across the road) in both the tins and also the frozen stuff. If I need to flavour it I will add Scopex or Strawberry just like the bait companies do. If I need red corn, I'll dye it with a dash of Sonubaits red dye (or orange or green ......). I've even dusted the stuff with curry powder (yup, it really works!!).
I tend to find that the cheaper varieties are firmer and bigger grained. The Smartprice frozen stuff is large grained and I boil with a little sugar and salt and then pack in suitably sized freezer bags. If I need to flavour or colour it I'll add it prior to freezing the stuff.
Your next question will no doubt be on the subject of super duper bait company tinned luncheon meat flavoured with exotic (and unobtainable to the average angler) ingredients like ....... curry powder, strawberry, halibut etc. Another bloody rip off.