It mostly depends on the complexity of the site (has it got javascript or other codes that need to be "taken care", logins etc).
I usually charge around 10 eur/ hour for how long it took me to write the script/bot (it's rarely more than an hour) and for the actual scraping (could take hours or even days) I charge something very low, like 2 eur per hour (realy it's just the cost of electricity/fixed costs, so it's free if you actually think about it). Then after the data is gathered, if it needs to be put in a database or excel, again I charge base on the 10 eur/hour rate (again it's usually less than an hour).
Sometimes I'm asked to do some mass image editing (not watermarking, much more complicated stuff). Again it follows the same pattern 2 eur/hour for everything automatic 10 eur/hour for manual work.
For example the past days for a repeat customer, I mass downloaded about 1000 images, mass edited them and sent them to be uploaded at their website. I charged 20 eur. How this was split (roughly).
10 eur for writting the script
2 eur download
10 eur for writing the batch file for the mass edit
2 eur for the batch process
=24 eur
It was 2 websites so 2 x 24 = 48 eur. Since it's a repeat customer, I charged 40 eur.
I have no idea what other people charge. It's a formula that I've come up myself.
