A bill of materials or BOM is a list of the raw components that go into a product. Most electronics projects, especially serious ones, will have a detailed BOM that describes the item and price that it goes for.
Often the final cost of the BOM will be much lower than the retail price because of the cost of shipping, R&D, profit margin, etc. Small changes in BOM price can have a big impact on the final cost of an item. It’s not uncommon to switch vendors or parts to save just cents on the BOM.
One trick I use is that multiplying the BOM cost by 4 will often get you the retail price.
