I would not pay 20 or 30 dollars for a single bottle of wine. (Can't afford it) We have enjoyed Barefoot wines and often find them on sale for around 5 dollars.I have also tried the Oakleaf wines during very lean times and liked them well enough.
The Franzia boxes are about 5 bottles and the price varies from 11 to 13 dollars. It stays fresh for a while because the bladder inside does not let the air get in. The trouble is you can drink way too much at once and be sorry.