First post after years of lurking, please be kind.
20% off all filament at Standard Print Co.
This filament has great diameter tolerances at +-0.03mm and prints really well in my Prusa. This supplier also does ECO-spools, so you can buy refils quite cheaply and re-use your empy spools.
PLA 1kg refil $22.40 ($28 with ECO-spool)
PETG 1kg refil $24 ($29.60 with ECO-spool)