If you are in the UK, and have an email address & postcode then you can use Klarna to checkout.
In most cases, you wont be asked for any card details during your checkout, instead you will be emailed by Klarna, so that you can pay for your order (within 14 days of placing your order) at your convenience. This is especially helpful if you are ordering on a mobile device. Sometimes, depending on certain factors, (like your address, the order value, the time of day the order is placed, your credit history) you may be not be given the pay later option.
Of course if you prefer not to use Klarna, or cannot as you are not in the UK, you can still opt to use PayPal (you do NOT need an account with Paypal).
How Klarna works: