The Shortest Bootstrapping Guide on IH Ever (no BS)
Or how we are doing it (as an apparel company).
Keep your day job
Develop and produce the first production batch with savings. The quantity of the inventory will be determined by your savings / per unit production cost.
BONUS POINTS: During development, create extra samples and give them away for free to start generating feedback, an early audience/user base, and in general, a buzz around your product prior to launch. Many of these folks will become your first customers.
Ship the whole inventory to your house = no recurring costs for storage/warehouse/fulfillment centers.
Fulfill all orders personally ($20 printer + some paper). Might as well include a handwritten note while you are at it.
By sticking to point 1, congrats, you have an unlimited financial runway.
Spend what you earn.
Price your product at at least 3x the production cost, this way you can spend what you earn for any marketing efforts + all other profits will be going into funding the next production batch, for AT LEAST the same quantity, you don't need profits for now (refer to point 1), you're building that vital early audience/community/fans.
Rinse and repeat. The process will scale itself.
Rely on content, word of mouth (have a VERY strong focus on product quality and functionality during the development phase), collaborations and giving away stuff for free (that's why you need a bit of a higher price point to cover those costs) as your marketing ammunition and in general spreading the word about your product.
Keep your day job, until you don't need/want to (the timing of this would strongly vary per person/goals/ambitions/discipline).
Now, all you need to do is to sell (duh), but that's where you get to learn marketing, branding, distribution and content creation without the stress of a limited runway or investors breathing down your neck.
Would love to clarify anything or answer ANY regarding this guide.