Okay, I found two databases with which to look up campaign donations in support of charter schools. The first one has been used to write some pieces on the subject, I used the site Follow The Money to run a query “Show me School Choice Advocates contributions to ballot measure committees that supported or opposed Vouchers/Charters ballot measures in elections in 2014 (within core federal, state, and local data)“ and it turned up nothing. But this appears to be a good database to use to check on what's going on with campaign finances.
A much more useful site, I ran a query on Campaign Finance Online for PA and found that a particular contributor, Joel Greenberg, contributed $350,000 to the Students First PAC in 2014 alone.
As to general patterns on giving to campaigns that support charter schools, I saw that in in Washington State, 91% of the campaign donations came from just 10 donors. Bill Gates, a Walton heiress and the Amazon people were among the donors. “Of all of the money raised for the charter school initiative, just one-half of 1 percent came from donations of less than $10,000.”
Over the past ten years, campaign spending in PA for and against charter schools has been $10 million for and $8.3 million against.
Among one of the lobby's biggest donors is Vahan Gureghian, the CEO of CSMI, which manages the Chester Community Charter School in Delaware County. According to Follow The Money, Gureghian pumped $336,000 into the campaign coffers of former Gov. Tom Corbett - making him his second largest individual donor over his gubernatorial career.
Gureghian has also donated close to a million to other Pennsylvania politicians and PACs.
The aforementioned Vahan H. Gureghian's Chester Community Charter School teaches 2,600 students. He's number five on a list of the ten biggest PA political contributors. Overall, he runs 150 charter schools spread over nine states.
A 2012 piece from Public Source includes detailed summaries for the 10 biggest contributors in PA.
Joel Greenberg and Arthur Dantchik are partners in Susquehanna International Group, which has used lessons from poker to build a successful broker-dealer firm. The two men spent $446,000 on groups that support vouchers for private schools such as charter schools. In 2010 their Students First political action committee contributed $4.9 million to pro-voucher gubernatorial candidate Anthony Williams, who lost in the Democratic primary election.
Former Governor Corbett was a big recipient of donations from pro-charter school interests and Republicans generally have received more, but some Democrats have received money for that purpose as well.