Hi malva,
Each person has their own methods and philosophy about this,, but I'll share my opinion. When I first started selling if I could sell the item and not lose money, I was happy. Building a selling account takes time. You need sales and feedbacks. Also, depending on the market, you have trial periods where your funds are not released until AFTER the product is received by the buyer. In those cases you need cash to buy the product from your drop shipper.
After my account and listings got established, I made small increases to the price until I reached the maximum amount that the item would sell for. Again, it goes to your own philosophy. As an example, do you want to sell 10 units a day at 3.00 profit or 5 units a day at 5.00 profit? Pricing is a delicate balance. Its more art than science.
If you are drop shipping, be happy to make a very small margin. You're not out anything but your time. You're not physically storing or shipping anything. You're pushing buttons on a keyboard and making money!
With the drop ship model, start with one product and keep adding until you reach the number of listings it takes to feel like you're making real money.
I hope that this helps you and I invite you to become a seller for my products too!
Ruth