It sounds simple but if you are web development company, you will be going to Pay Pal website at number of times for each project.
Pay Pal is widely accepted payment gateway for many businesses across USA, UK, Europe etc. Merchant options provided by Pay Pal are simply amazing. Fees might be high but the services are really overwhelming. From Express Check out to Standard Pro, each service is unique for each Business.
Digital Goods is the other best option provided by Pay Pal. No other Payment gateway provide this many services as Pay Pal does. Developers cannot forget Sand Box at all