Spigen Inc via Amazon offers a selection of phones cases from $9.99 as listed below. Plus, Prime members bag free shipping. (Non-members can spend $35 or more to get free shipping; otherwise it adds around $6.) The deals:

• Spigen Slim Armor Dual Layer Case for iPhone 6 in SA Gunmetal for $9.99 via "NBM5NMCH" (pictured, low by $10)
• Spigen Neo Hybrid Series Case for iPhone 6 Plus in NH Gunmetal for $11.99 via "9G2QRC6G" (low by $9)
• Spigen Neo Hybrid Series Case for Nexus 6 in NH Gunmetal for $11.99 via "TT479LEP" (low by $11)
• Spigen Tough Armor Dual Layer Case for Galaxy S5 in TA Smooth Black for $12.99 via "7WZ7SNQU" (low by $7)
• Spigen Tough Armor Dual Layer Case for Galaxy Note 4 in TA Gunmetal for $12.99 via "TGXVJ3C5" (low by $9)