Your product needs to be shown to the targeted customer and Sponsered ads backed by a long tail and highly focused or niche keywords is the way to go
Amazon offers cost-per-click advertising. You can see how much you’re spending for clicks on your ads, target keywords shoppers are using, and measure the impact of your campaigns. You can adjust your budget and bids at any time to test what’s working well, and to test new keywords.
I personally recommend a review every 15 days till you get your golden 10 keywords visited by shoppers.
Another feature worth mentioning here is Amazon offers ads in two formats.
1. Sponsored Products that promote the individual products you sell on Amazon. You choose which products to advertise, assign keywords or product attributes to target, and enter a cost-per-click amount.
2. Sponsored Brands which increases awareness of your products. The ad creative you build includes a headline, logo, and product images. When shoppers click your Sponsored Brand, you can specify whether they will go to the Amazon Store for your brand, or any page that displays your products on Amazon. You can showcase all products you offer by bringing the customer to your brand page and sell unlimited.
So, if you as an Amazon seller has never tried any of the promotional methods above, you may be losing some selling opportunities.
Only to manufacture, or keep in Inventory is not good but to market, sell and replenish Inventory is the need of the business.
Wish you success and luck. Start your Amazon journer here