Electrical wire is a broad term used by electricians and most people in the wire and cable field. The term means that if a manufacturer already makes THHN wire then they will most likely manufacture NM-B wire, UF-B Cable and Service entrance cables as well. However, something they might not manufacture would be welding cable because it's made with rubber insulation and it's under the category or power cables.
These are the things you should remember to ask your distributor before buying any electrical wire.
1. Which type of wire and cable are you most successful in selling?
If they only sell power cables or speaker wire, it might not be the right place to look if you are looking for electrical wire. If they only sell speaker wire, they may have exceptional prices for speaker wire and not electrical wire.
Distributors can get the best pricing by buying large quantities of products, just as with any other product. The less you buy, the lower your price.
2. Are you buying directly from the manufacturer?
Distributors sometimes buy very little wire and resell their products to other distributors because they don’t have enough volume to buy directly. It doesn't necessarily mean that the product you are receiving is inferior, but it will likely be at a higher cost. This means that there is an additional shipping charge and a mark-up in price.