Black Market stock rotates and refreshes; some items are gated behind market building level. Key F2P-relevant buys (gem-cost unless noted): 24-Hour Resource Production Speedup x1/x2/x5 cost only resources (recommended always-buy), x20 costs 3,800 gems; Tribute x1=30,000 resources, x5=300 gems, x10=500 gems (always recommended - best monarch-EXP value in the game); RSS packages: gold-buyable up to 5M for 1,763,000 gold, or gem-buyable at best rate 360 gems/M (500K or 500M tiers) - market level 30+ reportedly removes the gold-purchase option for RSS per user reports. VIP Time: 30 Days for 3,000 gems is the best VIP value overall. Not recommended: Stamina (50 for 300 gems - the store's 200 gems/unit up to 10 is cheaper; Shopping Spree event beats both at 800 gems/5), and Monarch/General EXP purchases (worse value than farming). Other notable stock: Medal x100/x200 (7,000/12,000 gems), Refining Stone x10/x50 (1,500/7,500 gems), Runestone Chest x10 (2,500 gems), Dragon Crystal x10 (3,500 gems), Scroll chests (6,075-54,000 gems), Gear Lv3/Lv4 (cheaper than store except Lv3 Intellect/Strength Crown), and gold-cost Equipment tiers Gold1/Gold2/Orange/Purple (120,000/28,200/10,400/3,700 gems) - dragon equipment never appears here.
Original research source: Evony Guide Wiki