Monoprice: MP Select PLA Plus+ Premium 3D Filament 1.75mm 1kg/spool, Black - $9.44

Monoprice is offering their black PLA+ 1kg filament spools on sale for $12.35. By adding $0.60 worth of filler and using promo code 'NY25', you can get an additional 25% off, bringing the price down to $9.44 per kg with free shipping. Check the product at https://www.monoprice.com/product?p_id=15833