Show a nicer error if trying to buy a domain without a credit card

lib/domains.js

@@ -8,6 +8,7 @@ const chalk = require('chalk')
 const Now = require('../lib')
 const isZeitWorld = require('./is-zeit-world')
 const { DNS_VERIFICATION_ERROR } = require('./errors')
+const cmd = require('./utils/output/param')
 
 const domainRegex = /^((?=[a-z0-9-]{1,63}\.)(xn--)?[a-z0-9]+(-[a-z0-9]+)*\.)+[a-z]{2,63}$/
 
@@ -156,7 +157,11 @@ module.exports = class Domains extends Now {
       if ([400, 403, 500, 503].includes(res.status)) {
         const e = new Error()
         e.code = json.error.code
-        e.message = json.error.message
+        if (json.error.code === 'source_not_found') {
+          e.message = `No credit cards found – please run ${cmd('now cc add')}`
+        } else {
+          e.message = json.error.message
+        }
         return bail(e)
       }