It depends on the level of education you already have.
There are courses offered by AWS, ASME, and API that address welding issues at different levels and tailored to their specific fields of influence.
Some seminars are offered by the local sections. The offerings may be one day to five day seminars that may even be offered on weekends. There are also courses offered by a number of colleges and universities that lead to degrees at the Associate, Bachelor, or PhD levels.
Pick your poison. Education is rarely inexpensive in the time needed to study and master the subject and the cost in hard earned cash. Sitting in a classroom alone isn't going to do much for you, you have to put the time in to study the course subject matter. That's were most people fail, i.e., the video games and television are more appealing and less tiring that actually studing.
Best regards -Al