We love Stripe. Built for developers first it provides a great user experience coupled with great rates. It is steadily becoming one of the major players in the payment gateway industry. What we love about it is there are no ongoing fees. You just pay for what you use.
If you don't have a Stripe account then you will need to sign up for one first. This can be done here:
In EventHQ to add Stripe as one of your payment methods simply go to Settings > Payments > Accept credit cards > Stripe > enter credentials > Activate
To find your Stripe secret Key and Publishable Key you will need to login to your Stripe account and navigate to Developer > API
This will then display you keys as per the image below. From this you can then transfer that information into your EventHQ account.
Once you have added your Stripe credentials the only other option you need to decide on is which payment card types you wish to accept. You will see that American Express is one such option and some retailers do not wish to take it as the charges they pay for accepting American Express are higher. It is our understanding however that Stripe charge the same amount. The only stipulation being that a higher charge is levied for non-european cards.