Nuts and Bolts for an online Start-up.

I'm beta testing a gift concept for women. It's a line of edgy underwear to give your BFF. I am looking for cost effective ways to market them organically. Can anyone recommend a great omnichannel app to help build community. We have a good content strategy but I would love some recommendations on must have apps/process/considerations etc. Any lessons learned from other startups would be wonderful. THANKS