To make 1 gram of antimatter, from E=mc^2, would take about 90 Terajoules. For reference, the atomic bomb that dropped on Hiroshima released about 60 Terajoules of energy.
So you would need at least (and with the efficiency loss of production, much more than) 1.5 Little Boy atomic bombs worth of energy to make a single gram of antimatter.
The Sun outputs the energy equivalent of over 4 million tons of matter every second. The same as the energy of over a billion hydrogen bombs every second.
Only a tiny amount reaches the Earth, and we use only a tiny amount of that. But if we could capture even a small percentage of the total energy of the Sun we could produce antimatter by the ton.
I always liked the star gate universe (?) series where the ships skimmed the stars they passed to charge up. We’ve essentially got a bunch of EV chargers dotted around the universe, although galaxy to galaxy might have some range anxiety.
So you would need at least (and with the efficiency loss of production, much more than) 1.5 Little Boy atomic bombs worth of energy to make a single gram of antimatter.