Bundle of Holding has two 13th Age bundles active for a month. The
13th Age Bundle contains the 13th Age rulebook, the 13 True Ways expansion, and the 13th Age Soundtrack for $20; if you pay $33+, you'll also get 7 more supplements. The
13th Age Adventures Bundle for $15 contains The Book of Demons, The Book of Ages, and Loot Harder; if you pay $28+, you get all 3 volumes of Battle Scenes.