You may learn more about the relative pricing of various 3D printing materials 
out here. Among polymers, ABS and PLA remain the cheapest materials we have to offer to our customers while castable resin and transparent resin are the most expensive.
If you would like to understand how we price the 3D prints at Fabforma, you may go through 
this query.
Please go through 
this query to learn about how you can reduce 3D printing costs for your project