Choose your favourite niche and go ahead next with choosing the right supplier for your product. If you don't have the necessity to construct your custom website, you could choose any of those shopify stores out there and plug it through the API to the supplier channel.
Next the most important thing, check the quality of the products to keep the refund rates low and do not burn your hard earned 2k on running ads extensively! Start with targeting small set of audience with a smaller budget, then scale out while you scale up! There are a lot of articles out there on the internet on how to effectively scale out the audience and scale up your ad budget. Wish you all the best!