Amazon offers the Amflo 300-PSI 1/4" Rubber Air Hose, model no. 512-25E, for $14.52 with free shipping. (Non-members can spend $35 to bag free shipping; otherwise, it adds $7.20.) That's $15 off list and the lowest total price we could find. (Similar models ship for at least $8 more.) It features 1/4" MNPT fittings.
Note that this item has an estimated shipping time of two to four weeks.