Why it's better to display prices without taxes?
In general, when you create an online store, youll want to open your market to as many customers as possible, which usually means the whole world (or almost). That's why most online shops will display the prices of their products without tax (VAT).
When you sell outside your taxable area, you do not charge taxes. There are exceptions, but that is the way it is in most countries. For example : If you are in France and you sell a product at 100 euros, the price of your product will be displayed at 100 euros and at the time of purchase, VAT at 19.6% will be added to the product price. The total amount of the invoice will then be 119.60 euros. If the client is in the U.S., the total amount of the invoice for the same product will be 100 euros, because the VAT does not apply.
This explains that the best way is to show prices excluding taxes and fees, which are added to the end according to country the client lives in.
If you want to include tax in your prices, you must not set the taxes in the administration of your shop and you need to display your products with the tax already included in the price. This way, the tax will not be added to the invoice.
However, remember that by posting your prices ''all taxes'' (VAT), you reduce the possibility of selling outside of your country, because customers will find that your prices are higher for no reason. In closing, being confined to a single geographic area (your country) is a way to reduce your sales without anything in return.