What is the minimum amount to buy a bond?

Could you please elaborate on the minimum amount required to purchase a bond? I'm curious to understand if there's a standard threshold across different types of bonds or if it varies depending on the issuer and the market conditions. Additionally, I'm wondering if there are any specific requirements or qualifications that an investor needs to meet in order to be eligible to purchase a bond, especially for first-time investors. Clarifying these details would help me make an informed decision about investing in bonds.