Chase issues some of the best business credit cards on the market for freelancers and small-business owners. These cards offer strong reward-earning potential and travel perks. Before applying, understand a few key rules and requirements.The biggest factor to consider is Chase's 5/24 rule: If you've opened five or more credit cards (from any issuer) in the past 24 months, approval for any new Chase card is unlikely. The good news is that most bu…