Will USPS give me flat rate boxs?

I sold a nikon camera and a point and shoot camera on ebay. I already printed out the labels and paid for it. Now if i go to USPS will they give me 2 flat rates box For free? So I can put my labels in it. I'm new to these ebay things.

Yes, when you go to the post office there are both priority and express mail flat rate boxes available for free. Just make sure you take some tape and scissors so you can attach the shipping labels.