The plastic for polytunnels is sold in the "agricultural cooperative" - a rustical warehouse trading mainly in agrochemicals.
I looked very surpised at my mother when she asked for "1 Kg of polytunnel plastic". The salesman also said: "No, no, we need to know how many meters you need." Of course. But after cutting the 1,5x8m piece he put it on the scales. The thing is, to cut the piece in the size you want it you have to say how many meters you need, but it is priced according to weight!
"Qual é coisa qual é ela
que se compra ao metro e se paga ao quilo?"
"Mas o que é que é aquilo
que se compra ao metro e se paga ao quilo?!"