The largest attributing factor to keyword ranking on Amazon is sales. This means, you need sales to get ranking. Search volume is not a good indicator of sales. For some keywords, there could be a high conversion rate, for example, 25% of searches result in a sale. Other keywords may have a low conversion rate, for example, 1% of searches result in a sale. Since the conversion rate can vary significantly for different keywords, it is not possible to provide estimated giveaways with a high level of confidence.
Instead, we suggest using sales numbers to estimate giveaway units. You need to match or exceed the daily sales of the top competitors in your market, for a period of 7-10 days, in order to achieve rank.