Prime members only. Amazon has the 400-count Amazon Basic Care Allergy Relief Antihistamine Tablets (Diphenhydramine HCl 25 mg) on sale for $6.50 - 5% off with Subscribe & Save (can cancel anytime) = $6.17 with free shipping on $35+ or with Prime. Same active ingredient as Benadryl Allergy ($15 for 100 tablets).