Cheap is deciding factor! Although I would pay a bit more if I could get a higher alcohol level because according to the article the saponins are released by the alcohol, so the higher the alcohol, the more saponins and the greater the benefit on cholesterol levels.
Spike the wine with some vodka?
One thing you might think about, is look for a wine with a screw cap. They tend to stay fresh just a little longer. And keep it in a cupboard or somewhere dark.