is there any priavte group of 50$ contribute?

http://www.steamgifts.com/forum/JriI8/small-invite-only-group/page/31337

I am going to copy-paste an answer from Marumisu

NO!!
Most giveaway groups have special requirements for joining or they recruit their own members. You can't just bluntly ask to be invited. In the worst case, you could be blacklisted in a group and forever prevented from entering it. And most groups only allow people who are active or contribute to join, so it'll take a long while before you'll be allowed in private groups. Just start being an active part of the community and you may get an invite of two.