Not to defend the JWs here, but I don't think there is anything wrong with them accepting donations for literature. Someone has to pay for the stuff to be printed....well, granted, it would be better if they weren't printing it at all, but from their POV.
Biblically, Jesus wasn't talking about accepting donations to cover the cost of literature or the cost of operating the church when he said "You received free, give free" at Matthew 10:8. He was sending the disciples to perform miraculous works such as healing the sick, raising the dead, cleansing lepers and casting out demons. That is what they were not to charge for. There are references to show that Jesus and the disciples accepted support for their work from those who approved of or assisted in what they were doing (e.g., Luke 8:1-3). And the concept of financial support of the ministry is brought up again and again throughout Acts and Paul's letters. In fact, pretty much the whole chapter of 1 Corinthians 9 is a discussion of, essentially, the need for a paid ministry. The WTS quotes verse 15 of that chapter out of context to argue against the idea of a paid clergy, since Paul, after making the case FOR a paid clergy, then in v. 15 he says that he personally did not accept support from the Corinthians so that nothing would interfere with his message. The JWs take his unusual exception in this single case and try to make it the standard for all leadership, ignoring everything else Paul wrote in the chapter.