Best execution wins and best name (which is a part of execution). Put a lot of thought into naming your product. A name / brand can be defended - an idea cannot.

Sounds like you are doing a subscription box. The buying at retail idea is a good way to start. Start an IG and see if you can build interest and followers interested in your general category. You can start selling after you have built a following (by injecting an ad based image into your IG feed once a week and so on.)

The way subscription boxes become successful is soliciting / attracting product for consideration. The products are donated to the subscription box company as part of the product manufacturer's marketing effort and that's how you approach the manufacturer - by offering a MARKETING or promotional opportunity. If a subscription company has a big enough subscriber follower base the manufacturer might actually pay a placement fee to have the product included in a subscription box mailing. If I make xyz lipstick and you have 10,000 subscribers who like lipsticks, it makes economic sense for me, as a lipstick manufacturer, to pay you to send my product to those highly targeted subscribers.

On the other end you market the subscription box as a lifestyle product (not a whiff of how you acquired the products for free.)

Getting the ball rolling though is the tricky part for subscription boxes. IG is without question the best platform for lifestyle image type products like subscription boxes. Start there.