@Radvis no need to pay for anything, you can find the tool free on github :
https://github.com/termuxprofessor/Telegram-Scraper-Adder
this worked for me, all you need is python. Dont edit the files just open cmd and python setup.py after u set it up go with 'python scraper.py' and scrape group members you want to add. after that just 'python adder.py' and choose the group you want to add the members.
I think this works for groups only ( don't know since i used it only for groups), you can add up to 50 members/day with one account and than you will get flooding error from telegram.