That's a bit like asking "how much does it cost to build a house?"
Prices vary over a huge range depending on which robots you buy, the complexity of your process, what additional hardware you're using, the quality of the programming you hire, where and when you're having the work done, any number of things.
You probably should contact a reputable systems integrator and ask about getting an estimate.
I know that question is incorrect and indecorous, but as I already mentioned I need just any source with any information.

If you can find something with precise facts like: price for programming of Kuka robot for welding and etc. That would be also great!