Since labor makes up the bulk of the welding costs, anything you can do to save the welder time can help reduce your costs. If possible, handle any prep tasks on your own. This could include cleaning and preparing the metal surfaces before the welder arrives and gathering all necessary materials and equipment in advance.
Additionally, simple welds take less time and cost less money, especially on custom projects like a gate or fence. Look for waqys to simplify the design of your project without compromising the functionality.
Finally, opt for mild steel over more expensive alloys when possibly. Mild or low-carbon steel is generally the most affordable and easiest metal to weld, which may allow the welder to charge a lower hourly rate.