If you want to save your time, do not go into setting the exact price. Set all the prices a little on the higher side − higher than the viable sales price of the product. Then using some pricing tool, modify the same as per the set of rules in the tool.
Amazon has a repricing tool that could be quite useful. Merchants need to use such pricing tools because prices change very quickly with upcoming new merchants and new inventories. So, one needs to keep a check and keep the prices reasonable without making any changes manually. These tools use Amazon Web Service’s Application Programming Interface (API). They track information about your pricing and your opponent’s pricing and modify your pricing to appear more competitive, thereby escalating your sales and drawing you closer to the Buy Box.
Amazon has no objection to merchants using these tools. In fact, they understand that managing large number of products isn't possible without automation and they like tools with a tendency to push the pricing down, because it provides lower prices to their customers.
You may also identify the maximum and minimum price limits you are comfortable with and automate pricing. This will automatically adjust your prices within the competent range. The only thing to be cautious should be the Minimum Price field. Users who are new to the repricing tool may lower their prices below a reasonable limit and may suffer heavy losses. So, these tools have been laced with a wide range of different settings that allow you to protect yourself from pricing items too low.
There are a variety of rules that decide how and when the tool should change your product price, how to deal with FBA and non-FBA products, and which products and merchants to price against. Depending upon the program and the price of the service, you can decide upon the schedule of how often you want the tool to reprice.