Starting a business or ramping one up? If you'll be buying a lot of equipment or paying for office space and supplies, it helps to put those expenses on a credit card with a low interest rate.

With the Citi Diamond Preferred Mastercard, you'll enjoy a 0% initial APR. Even better, that rate lasts a full 21 months. So if you're planning to make some big-ticket purchases, this card is a great way to get what's essentially an interest-free loan. And you'll have almost 2 years to pay it back.

After 21 months, your APR will rise to anywhere between 11.99% and 21.99%, depending on your credit score. Hopefully you'll pay the card off before that kicks in.

Meantime, every big-ticket office purchase helps you rack up points for getaways, says Gonzalez at CardHub.

The card also provides a 24x7 concierge service to help you book flights, hotels, concerts and more. Plus, you get special access to ticket presales, preferred seating, VIP packages and more.

There is no annual fee.

If you're interested, apply now, advises Gonzalez at CardHub. With Fed rate hikes looming, that lengthy 0% APR might shrink next year, she says.