We find that the better quality filament gives better results, regardless of the filament cost. Costs vary with quality, quantity and shipping.

Generally, the better quality filament providers charge more.

If I am making prototypes, perhaps my concern is cost more than quality: I would select lower cost material in this case.

If I am making production parts for resale, perhaps my concern is quality more than cost: I would select higher quality material in this case.

We also find that keeping your filament dry and printing in a dry (and filtered/ventilated) area can help with output quality.