Can I mail my State tax return ground advantage usps (first class large envelope) to save money even though I am getting refund from state of CO?

[sandrawa]

Can I mail my State tax return ground advantage usps (first class large envelope) to save money even though I am getting refund from state of CO? 

I don't plan on owing money but because it is refund they are asking I mail in my return. Since first class mail with tracking is cheaper than priority can I ship it using this method? I do plan to drop it at post office and get receipt 

[ee-ea]

You have a great plan.  Do it.