Off the top of my head here are a few suggestion's: building a website is relatively easy now and there are plenty of free sites : www.wix.com
Somebody has helpfully suggested where to get a logo.
Costs are financial and time invested to raise awareness of your business.
Good quality images of your products = good quality camera.
Deciding if you want to spend on advertising and where?
Attending to events and exhibitions (so thinking about displays and having enough stock to sell).
Producing promotional literature.
developing your online presence via social media so always posting on Instagram, Facebook, youtube, pinterest etc.
I'm thinking about starting a small business next year, so I've been watching the growth a few small independent labels to gain ideas. I'm currently being stalked by fashion nova, I put an item in my basket and now they're messaging me via Facebook messenger to remind me to buy the item in my basket! I'm surprised at their speed and don't recall sharing my email so how did they do that?? Anyway, I've digressed.
Good luck xx