I agree with GoldenOldie about USPS. I checked their rates, expecting them to be the lowest and found them not only more expensive, but they did not guarantee a delivery date. If I were you, Id go to the UPS and FedEx websites and find out the maximum dimensions of a regular-sized package (if your package is oversized, youll pay extra). Your shipping cost will depend on if your package is regular or oversized, the package weight, the distance you are sending your package and the type of service you choose (regular ground delivery up to overnight, with guaranteed early morning delivery).
To give you some idea, I shipped a regular sized, 30 pound box by UPS (regular ground delivery) from St. Louis MO to Lake Buena Vista for about $15. The guaranteed delivery date was three days after I dropped it off. It arrived on time. After you ship your package, you can check the status of your package online (I knew before I left for Florida that my package had arrived at my resort and I had the name of the person that had signed for it.