Pricing of products is as much science as it is an art. Generally there are 2 types of products - commodity and more or less unique. Apparel is more unique unless you are selling known brand who's same products you can find at many other retailers. Definition of commodity is that same product is available at many places to buy. I'll try to explain how to set price on each type. In all cases the bottom price is determined by your cost: product, shipping, advertising, ... This can be different from retailer to retailer as they may acquire product at different costs. If you are making the product than your cost is unique and the only one relevant. Then there is also the top price you can set. Top is more complicated and I explain it below. Generally you will set price somewhere between.
Commodity products
With commodity product, like a phone charger made by known brand and sold at numerous places the price you set is determined in addition to your cost also with prices that other retailers sell it at. If same charger costs less on Amazon than in your store, you need a very good reason to keep it that way. What else do you offer to justify this higher price? In most cases you will find it hard to sell at prices that are more than on Amazon. Many who sell on Amazon use dynamic price algorithms to continually adjust price relative to competition. Needles to say this is a very dangerous game that can quickly lead to rock bottom prices on commodity products thus depriving everyone of any good profit margin.
Unique products
With unique products and especially if you manufacture them and control distribution you have more freedom setting the price. However in most cases there will be substitutes to your product so unless you are a top designer you are still bound to some limits. Generally the higher the price the less people will buy. This brings in some interesting math. Do you prefer to sell 20 pieces at $200 each or is 12 pieces at $300 better. If you can't answer this you need to take a math class.
What most people buy on is value or price. To explain value is best with example. If you can get 6 socks package for $20 it is better value than 3-sock package at $13. But you may not need so many socks so you go for a less valuable package. Retailers play this game all the time to get you spend $20 instead of $13 and each pair of sock probably costs them $1 or less. Here we are already getting in use of pricing as strategy.
Strategies
Another strategy is to offer penetration pricing in order to gain market share or drive out competition. Many Chinese companies are accused that they sell below their cost in order to introduce their new products to buyers and when buyers change their image of products and competition is gone the prices are raised. While this is illegal it is hard to prove. After all, products made under certain conditions can cost very little to make. Not saying more.
Therefore, in summary, if you want to find the right price for your product, first determine its cost then research competition and substitutes for top price, and finally experiment with price between the low and top bounds to maximize profit. Hope this gives you some ideas and help.
