[DamonHD]

1) Work paid part time at something else.

2) Join an accelerator or similar.

Both have worked for me. There are other solutions too.

[apothegm]

Also bank loan. But risk.

“Friends and family”/angel investors, too.

[billconan]

what if your project is a niche, you have no plan for an exit, how do you share profit with the accelerator?

[DamonHD]

Not all accelerators take equity. Some are pure grant funded such as one I used.