What country are you in? Does the material in the package violate any shipping rules for the various carriers that exist in your local? Do you need to track the shipments? Is the shipment time sensitive? And where are you shipping from and to?
In the US, you have the choice between US Mail, Fed Ex, and UPS. US Mail prices are fixed. Both Fed Ex and UPS prices can be negotiated based on shipping volume. So there is no easy way to give you an indication of who has the lowest price.
All three carriers will send a truck to pick up your items. You don't load the truck, they do. You may have to pay a fee to ensure daily pickups. In addition, if you negotiate a price based on shipping volume and don't meet that volume you will probably pay much larger shipping fees.