Free truck driving training usually refers to programs offered by trucking companies or truck driving schools that are sponsored by trucking companies. These programs provide hands-on driving experience, and training in industry-standard operating procedures, and can lead to a job with the sponsoring company. The only bad part is you have to work with that truck company on their terms. They decide your pay rate and basically your bind by a contract, you cannot get out of the contract till pay them back or pay it off.
Paid truck driving training refers to programs offered by truck driving schools that are not sponsored by trucking companies, and typically require the student to pay for the training out of pocket. These programs offer the same type of training as free programs, but the student may have more flexibility in terms of choosing a trucking company to work for after graduation. The cost of paid truck driving training varies depending on the school and the program. Once the student gets their CDL they are free to choose any trucking company to work with that matches their pay expectations.