Many high quality charter schools have helped families get an excellent education for their children. Most of these families could never afford a private school's tuition and, were it not for the charter school, would be forced to send their children to a failing public school where they would not receive a proper education. Your argument seems to be that since the charter schools cannot help EVERY child then they should not help any children; that seems ridiculous to me.
As for the lottery system, it is legally required for a charter school (which, although not part of a school district is still a public school of choice) to select its students in this manner. Charter schools are not allowed to base their admission on academic ability or social connections (i.e. the parents are friends with the Dean or the parents are influential in the community etc.). That discriminatory garbage is reserved for private schools.
Personally, I am all for charter schools. A charter school is like a laboratory where educational methods can be tested and proved. Charter schools have PROVED that you can take a kid from a poor background, a bad neighborhood, a history of poor academic performance, and you can properly educate that child and send him on to college and a good career! It is simply amazing and worthwhile work that is being done in the good charter schools (I will not argue that not-so-good charter schools also exist, but they generally do not last long). The hard part is applying the lessons learned (by educators) in charter schools to the rest of the public schools. Unfortunately the system is so broken that it clings to its worst attributes and fights and screams when anyone attempts to reform it. This is why I am proud to support high quality charter schools in the meantime.
Also, I have never heard of a charter school requiring parents of the students to donate anything other than their time. It is probably illegal for a charter school to require donations, are you sure that the school in question is doing this or is it just a rumor?
Update:
So it sounds like the charter school you are dealing with IS doing some illegal and/or unethical things, I can see why that might sour your view. But I maintain that it is the exception, not the rule. And if your problem is really with the lottery system then what IS your answer to it? Let in only the "smart" kids who "deserve" a better education? Really, what is your opinion, because just complaining that the lottery isn't fair and may hurt some kids feelings doesn't do anyone any good. I commend you on wanting to help children succeed academically, and I wish you success, but you WILL have to limit the number of students you help, there is no getting around it unless you have unlimited funds and facilities. No matter how you select your students someone is bound to get their feelings hurt and claim that the process was not fair, and yes, that’s the nature of life.