UPDATE: Are you going to the ticket sales link directly from the Disney on Ice website? I did, and I'm not seeing very many seats in that range; other than the rinkside seats, most of the first tier tops out at about $80, and there are very good seats available for some shows for about $30. For Boston, they are also offering a hefty "Me + Three" deal on 4-ticket packages, so you might actually save money if there is a second grandchild or a friend who might like to come.
Agganis Arena also has a public box office, and sometimes, if you buy in person at a box office they waive all or part of the service fee; it's worth a call to ask.
The resale sites have the prices jacked, but going directly through the link from the tour homepage seems lower.