I grew mine very slowly, initially working from home, then renting a room and now renting a whole barn and sub letting part of the premises.
Because I had a steady client base, I saved and bought a bit, saved and bought a bit so I had all my products, machines, trolleys and couches. When I had the floor put down I paid it out of my business but when I had the dividing walls etc put in, I got an overdraft facility to pay for it. I did it on a budget and did a lot of the work myself. It was a really hard slog but the salon looks fab although we're still not finished.
Having a steady clientele has helped as I have had steady money coming in. We're now more or less where we want to be but money is still incredibly tight.
Good luck with it all
Vic x