The spinster sisters revisited

This sentence occurs in the piece mentioned in my last thread under Modern Greek language queries:-
Ξέρουν πού πουλιέται τό καλύτερο καί του φθηνότερο. What does it mean? Πού thus accented means in this little book means 'who; which; that; when'. When it means 'where' it is accented ποῦ. Does the sentence therefore mean 'they know when the best & cheapest [stuff] is sold'?:)

Ξέρουν πού πουλιεται τo καλύτερο καί το φθηνότερο, is the correct sentence. They know where to buy the best and cheapest.
Not του φθηνότερο unless you are from Sterea Ellada/ Roumeli, in which case it is του φθνότρου, and this is an attempt to mock how people from there talk, so don't take it seriously.
In modern Greek there is only one accent, therefore there is no ποῦ (interrogative pronoun). However, in order to maintain the distinction from the now non-accented που (relative pronoun), the interrogative pronoun is stressed.

PS Scroll down to Exceptions where monosyllabic words do receive an accent mark form more detail

Thanks again, SBE! The του φθηνότερο is my error. It should be το as you spotted. But the error sparked off a very useful note about the Sterea Ellada/Roumeli! It is worth a tsamikos in your honour. I should mention that when I went to Delphi village with a school party one Palm Sunday shortly after I became Orthodox thirteen or fourteen years ago, the old lady who owned the house & hotel where we were staying, adopted me & whenever we met she showered me with gifts. I have very many happy memories of Sterea Ellada & that Κυριακή των Βαΐων......