Your secured credit card’s security deposit is ultimately a matter of personal preference. Secured credit card issuers generally require a minimum deposit of around $200 and allow you to put down as much as $5,000 or $10,000, but the exact amount is up to you. The reason for this is that your security deposit acts as your credit limit, which ensures both that your issuer will get paid back and that you cannot spend beyond your means.
There are a few of important things to be aware of when deciding how much to deposit. First, as mentioned, the amount of your deposit will be your credit line, so you need to deposit at least as much as you wish to spend per month. Second, your credit score will benefit from low credit utilization—your monthly balance compared to your credit line—so it’s a good idea to only spend about half of your deposit amount each month. Third and finally, your credit score will also benefit from a high absolute amount of available credit, so deposit as much as you can now in order to get positive information flowing into your credit report and add to your deposit over time.