Nowadays one of the biggest drawbacks in 3D printing is the relative high cost of filament, i.e. the 3D printer (thermo-)plastic, the “consumable” for your 3D printer. Prices for 3D printers have been continuously dropping, but filament prices did not really follow the same path. Agreed, filament availability is far better than 2 or 3 years ago, as are color choices. Even the materials for 3D printing are becoming more and more varied and readily available.But prices, especially for good quality filament, did not really drop. Although we are witnessing a rise in competition between industrial filament producers, which in the long term should result in more mass production and overall lower prices, filament prices still hover around 22-30$ per 1kg spool. You even pay up to 50$ for 500g of specialty filament. These prices are so high partly because manufacturing and selling filament is a very lucrative business.
Source: An introduction to DIY filament extrusion and extruders | 3D Printing for Beginners