If you don't have $400 then you won't be able to work this plan If you need to, you should borrow the money from a friend, or even from many. Then go to a bank of your choice and deposit the $400 into a regular passbook savings account.
In a few days the account will be posted and you can return to the bank to ask for a $400 loan - against the passbook savings as collateral. With the $400 you are going to be able to go to another bank, and open another savings account there. You repeat the waiting for a few days and then the borrowing against the deposit as a collateral. Then, with your borrowed $400, you go to another bank, open a savings account, return a few days later, borrow $400 from that bank using your passbook as collateral.
Then repeat the process at a third bank with your borrowed $400. In the fourth bank you will open a checking account instead of a savings account. Wait a few days and make a payment on each of the other three loans. Wait for a week, and make another payment on the loans, and keep on paying off the loans, until your $400 is almost completely gone.
If anyone looks at your credit history, they will see that you have three bank loans that are active (which are considered hard to get), and that you also have a checking account, and you have a history of paying the loans before the payments become due. This type of person, who has all this going, gets A1 Credit rating... in the short span of thirty days. With an A1 credit you can apply for "real" loans, credit cards, and even buy stuff on credit.