I don't know if this article crossed your radar. 

It's heartbreaking. 

Catherine Hettinger from Florida invented the latest kids' toy which has gone viral in the last few months. 

Very sadly for Catherine however she let her patent lapse because she could not afford the renewal fee of £310. She will therefore not be making a penny from her own invention.  

If any harsh lessons are to be learnt here, it is the  crucial business imperative to get fully IP protected. I have posted elsewhere that many talented entrepreneurs either are not up to speed on IP in general or, if they are in the know, they seem to feel they will worry about IP when and if their invention takes off. As this case sadly proves, often that will be too late.