It "ain't", but it's called capitalism...perhaps its' seedier side. Usually four tickets is the maximum allotment per purchase.
I say you complain to PF, the arena, and if you're really motivated, the legislature.
If you tell PF you're not going because the ticket price was quintupled, I'm sure they'll lend an ear...they want to keep their fan base.
The arena won't care as long as they sell out.
The legislature should care, as it protects consumer interest, and the quintupling of ticket prices reeks of usury.
I'll have to see what happens with PF in my market. Cheers.