I think it's a very neat store and has great potential!
But here are some suggestions:
As a first-time visitor, I had no idea what the site was. I had to kind of explore to figure out. Visitors need to be able to immediately know what your site is. (Like literally within 5 seconds of visiting)
Add a tagline for your header that says something like "Offering name-brand retail at a lower price" (like you said in your about section)
Later on your home page, you can share your story and explain how you buy overstock, damaged items, etc. and redeem them
Right under your tagline you need to have a clear call to action button that says something like "Shop Now" and takes visitors to your outlet page. Again, at first I wasn't sure how to find your products.
I would delete the blog. Obviously you haven't built that yet, but I don't think it is necessary and you want to keep things simple and not overwhelming. You want to narrow down your navigation buttons because right now they are spilling on to a second line because there is not enough room for them on one line.
I recommend choosing a more modern font and possibly using one of the Squarespace templates for a more modern, beautiful look for your site overall. Also adding pictures like in the header would help.
As far as the membership, I think it's a neat idea and maybe people would join (the price is definitely not too high) but because your store is so diverse I don't think most people will be shopping from you on a regular basis. I would expect people will be searching for a specific item and come across your store because the item showed up in search results (so be sure to identify and tag everything well in your store).
Maybe create a logo for your store instead of just text. There are free logo creating sites that you can do this with.
Hope this info helps!