Wirelessly posted (BlackBerry: BlackBerry8530/5.0.0.1030 Profile/MIDP-2.1 Configuration/CLDC-1.1 VendorID/417)
"if you buy on board, you'll pay an extra $5.75 fine per ticket."
Unless you qualify for the senior/disabled fare.
One could also take the LIRR just from Ronkonkoma to Jamaica (lower fare), and take a subway from there to lower Manhattan.