Need help determining best shipping practices

I intend to put up a pair of speakers for sale, and I am trying to figure out how to price them regarding shipping cost. What do more experienced A'gon sellers use, UPS Ground, Fed Ex Ground, or >gasp< USPS? Is there another option? The speakers+packaging weigh 35 lbs each, 1'x1'x4'. Thanks. PS - this is the first time I've sold speakers on A'gon. Can you tell.