D&D Dungeon Master’s Guide & Other Core Rulebooks (5th Edition)

Amazon.com has low prices on Dungeons & Dragons Core Rulebooks for 5th Edition right now. Shipping is free w/ Prime or orders $25+.?

• D&D Dungeon Masters Guide – $23.98 – Link
• D&D Players Handbook – $27.27 – Link
• D&D Monster Manual – $23.98 – Link
• D&D Xanathar’s Guide to Everything – $22.45 – Link