Without knowing a budget, interests, space, or any other constraints... Maybe a starter-tier 3D printer. Something around $300~. You'll need a well ventilated

Without knowing a budget, interests, space, or any other constraints... Maybe a starter-tier 3D printer. Something around $300~. You'll need a well ventilated space though, plastic fumes are unpleasant. Or a basic CNC if you don't want to worry about fumes, but then material costs (i.e. wood) is much higher than 3D printer filament.