Why you want free followers on twitter?
I would say, don't rely for the other websites to get followers. Start working yourself to get followers on Twitter. Make routine, stick to it. Follow people from the related niche and see their activities and try to follow them.
What more you acn do, ask him to follow you back, retweet some of their tweets. before getting anything make yourself noticed by other.
I have seen many people who boast of having over 50,000 followers, but, like Dani said, how many of them actually actively read all their tweets? I only have about 2,600 and something, and that gives me plenty of trouble, answering RTs, MTs and such. I'do go crazy if I had 50,000 followers and had to answer all of their messages to me! My followers DO respond to me, and that is what you want, you want real people that will notice your messages when they pass through their feed. You want them to retweet your messages to their own followers (that will extend your reach) you don't want just to inflate your numbers and have nothing in return! Love your followers, give them something of quality, talk to them, nurture them, and they'll grow over time. Wish you well!