There is a big sweet spot for shipping LTL. LTL means less than truckload. Most carries will allow you to ship using LTL rates up until you are shipping 6 skids. Some will let you ship 8. When you consider that a standard 53 foot trailer can hold 26 skids if loaded correctly, as you get above 8 skids you get into half truck territory. We can't actually get 26 skids in a truck. We usually max out at 24. We used to floor load most orders so that we could maximize the space in the truck. It is still often the cheapest way to ship but most big customers want product on skids. In order to ship LTL affordable you need to have discounted rates from a carrier or a broker. There are many national LTL carriers and many local. We primarily use Roadrunner and The Custom Companies. Both carriers will come to our place to pick up the goods and will drop it off at their service center. Eventually a truck going closer to the target address will take the goods and bring it to the next station. Eventually the good will get delivered to the final destination. With roadrunner it will typically be a Roadrunner truck that does the delivery because they own their own vehicles. For Custom, they will probably sub it out to a local delivery source when they arrive in the area of the destination city.
After you get past 6 skids, you need to decide if it makes sense to split the load and send it as two LTL loads using two different carriers or should you send it as a half truck. We have done both, but it is usually cheaper to send two LTL loads. You can sometimes send both loads with the same carrier but you need to watch out because they will put the two loads together and adjust your pricing. If you have the time, send them a week apart.
When it comes to LTL you need to negotiate what is called a FAK or a Freight of all Kinds. This allows you to ship all of your freight at a set freight class. Let's say you ship lots of sold metal parts that are class 70. You could negotiate with your carrier that everything you ship in class 50 regardless of commodity. We have negotiated lower classes for our furniture in many cases. You can also negotiate the accessorial charges like lift gates, residential, and inside delivery. You also want to negotiate call ahead service and make sure you don't get charged for that.
Now that you have your LTL carrier, you can find other ones and have them try to match the rates of the first one. You always want to have a few carriers just in case.
To calculate the freight class of your goods try this link