B2B is the transaction between a business to another Business.
B2C is the transaction between a business to customers.
In B2C, the business will directly sell the product directly to consumer. The quantity purchased by an indidual customer will be less. The rates will be fixed and all will get the material at almost the same price.
In B2B the business will sell the product to another business where they will use that product in their business.
Generally B2B will be a little complicated and time consuming. Many systems and procedures will be involved. The person who is making the purchase may not have the final authority to make the decision of purchase. A team may be involved in finalising the product. The team may have persons from technical department, quality department, finance department and other departments as required. They may ask quptatios from different parties manufacturing the same product. They will compare the rates, quality and the suitability of the product for their process.
The price from one company to another company for the same product may differ. The price depends on many factors like quantity, packing details, quality requirements and the negotiation skills of the purchasing company. The price may be on the higher side to government organisations as there may be many hidden expenses.