Daniel (@dungeondive) gives his three concrete starting-point recommendations for solo RPGs — each capped at roughly $30 to keep the barrier low — plus one bonus pick for total newcomers.
Bonus (gamebook newcomers): Fabled Lands. A multi-volume keyword-tracking gamebook series with light RPG bookkeeping; the open-world structure trains you for sandbox play without demanding a system yet.
Pick 1 (weirdo metal): Mörk Borg with the Solitary Defilement solo system and the Feretory supplement. Tiny core rules, vast supplement ecosystem, and a death-metal aesthetic you can dial down to standard dark fantasy if it’s not your thing.
Pick 2 (traditional dungeon crawl): D100 Dungeon core book plus the World Builder. Roll-and-write OSR comfort food with a hex-crawl layer for adventures between dungeons — Daniel calls World Builder one of his favourite expansions for any game, despite the layout being rough.
Pick 3 (the broken-record answer): Scarlet Heroes by Kevin Crawford. A single book containing the full Target-20 system, solo rules, urban/wilderness/dungeon procedures, and his Adventure Tag generator. Pair with the $5 White Box if the pan-Asian bestiary doesn’t suit you. Daniel’s all-in-one pick for sword-and-sorcery solo play.
Of these three — Mörk Borg, D100 Dungeon, Scarlet Heroes — which served as your actual on-ramp into solo, and did it still hold up after you’d moved on?