For me, quality plants are those that will most likely survive and grow vigorously when I get them. The quicker they grow and the earlier they fruit, that is quality to me.
Poor quality plants are those that would need a lot of baby-sitting, special care and ideal conditions. If given a choice, and their prices, it would depend on what my circumstance and current state of mind, but would gladly go for a higher quality plant if the price is right. When a cultivar is newly acquired in my collection and rare, the most important thing that it is alive when I got it in my hands, and if the quality is poor, I can tide it through using my knowledge and skills in plant growing. I have even made a plant grow out of the worst banana seller that I have ever encountered, these are the sellers from TyTy nursery who shipped to me tiny banana corms that are rotten. I have to build a special chamber to resurrect them from the almost dead conditions. I kept it almost sterile, warm, very humid, and always applied fungicide when trying to grow them. Here's the "Lazarus" chamber that I made:
http://albums.photo.epson.com/j/Albu...&a=31143051&f=
I spent more time and resources the financial value of which is several times more than the price difference between high and poor quality plants. But sometimes, I just have to go for the poor quality plants because I love challenges, and when after several tries become successful, that would be a priceless experience.
Unfortunately, not all plant growers are like some of us who would have above-average knowledge and skills, would love challenges of growing them in marginal climates, pushing them above their limits. Surely the poor quality plants would most probably end up quickly in the landfill or compost heap in the hands of average homeowner. Most people would not have patience to wait that long either, nor have the care and time to do the extra special things to care for poor quality plants.
But poor quality plants are inescapable facts of life, life may simply hand you the worst stuff, but you can take the challenge and learn how to properly bring these poor plants to fullness. "Sometimes" I would go for them at a price that they are supposed to be valued, but not always, it just depends if I will be busy with other things at the moment. We have various goals or purposes of growing plants, and sometimes our goals changes with time.