[header] How to buy premium bonds [title] Decide if ns&i premium bonds are right for you. [step] Ns&i premium bonds are a savings account you can put money into and redeem at any time without penalty. Note that you cannot get withdraw your investment instantly like a bank account or isa. 
With these bonds, the interest you earn is based on a lottery system. Your bond number is put in a system that randomly draws a certain number of bonds per month one calendar month after purchase and will continue to be entered until you cash in your bonds.