I find that 380 is even cheaper to reload for than 38 special. The bullets cost less because less lead is used to make them and the powder charges are smaller because less powder is needed. As for assembling the rounds, it's not any more difficult that any other semi auto and the do require less effort at the press than something like a 45 ACP.
The only difficulty is with the powders available. I would really like to use 3N37 because it's been very clean shooting for me in 38 special but there isn't any available data for this powder in this caliber. So, I am stuck using CFE Pistol which is extremely sludgy at low operating pressures and leaves my pistol a mess. BTW, my Sig P290 requires top of the chart loads for reliable function and I've found that using Accurate #5 just doesn't provide enough energy for reliable ejection. So, I use CFE Pistol because it's the ONLY powder I've found that provides for reliable ejection.