how can i turn on/off pay as you go data?

Pay As You Go Data can be turned on/off at any time through: 

• • My Account
  • 1-800-CRICKET
  • Cricket company stores and dealers

If you regularly find yourself using Pay As You Go Data you may want to look for a rate plan with more Full-Speed Data or add a Full-Speed Data Add-On to your plan, if available.  Those options will likely be a better value.