service providers. Companies like those often need to float the costs of supplies and services before getting paid by their own customers. Plum Card takes the classic American Express charge card back to the future, since it carries no preset spending limit and up to 60 days to pay a balance. Get cash into your till sooner, and a 1.5-percent early payment discount can help cover the flat annual fee of $185. American Express covers the first year of fees for new members, and the Plum Card includes extra cash back rewards from participating OPEN Network merchants.If you spend big on client meals and office supplies:Ink Cash Business Card from Chase. If you've been in business for a little while and you've got great credit, Chase would love to reward you with up to 3 percent cash back on your everyday office purchases. Any other purchases on the Ink Cash card earn 1 percent back, which you can stretch even further by redeeming for discounted merchandise and gift cards from Chase's partner network. Your bookkeeper will love access to Blueprint, Chase's online tool that helps you plan the payoff schedule that will save you the most money.To save on travel expenses and supplies:TrueEarnings Business Card from Costco and American Express. Plenty of small business owners already use the personal version of the TrueEarnings Card, since it doubles as a Costco membership card. If you're ready to move risk from your personal credit report onto your corporate profile, American Express will repay you with significant cash back rewards. This card rebates 4 percent on gasoline purchases and 3 percent on restaurant tabs, two of the biggest purchasing categories for road warriors. You can even save up to 25 percent extra on purchases from a network of preferred vendors, including JetBlue, Hertz and FedEx. Your rebate arrives once every year as a voucher you can redeem at Costco, and there's no additional annual fee.For the business owner on the move:U.S. Bank FlexPerks Business Cash Rewards Visa. This one-time regional lender has grown into one of the top five banks in the United States, thanks to its dual focus on service and innovation. FlexPerks cardholders earn 3-percent cash rebates when purchasing gasoline, wireless services and office supplies. All other purchases rack up a 1-percent cash rebate, which cardholders can redeem in $25 increments. There's no annual fee, as long as you make at least one purchase per year on the account. Best of all, you'll receive a 25% bonus on all your cash back rebates on the first anniversary of becoming a cardholder.For cash back and streamlined accounting:SimplyCash Business Card from American Express. SimplyCash may not get as much press as its Plum and TrueEarnings cousins, but it offers plenty of great benefits for prospective cardmembers who have been in business for two or more years. There's no annual fee, and your cash back rewards show up every month as statement credits. This card pays back 5-percent rebates on wireless phone services and on office supplies, two majo