Parking is free during the weekend. During the weekdays it is a few bucks per day. If you expect to be there during a weekday period, there should be able to buy tickets right there.

There is long-term parking at the Poughkeepsie train station. Make note of the space number where you park. Go to the one of the machines either on track 2, on Main Street, or on the concourse level of the station. It's $2.50 for 16 hours or, I believe $4 for 24-hours. You also have the option of paying for multiple days. Cash only, no credit cards. Make sure you hold onto you receipt. You don't need it to get out of the lot, but it's your only proof if you get a ticket. As the previous writer noted, there is no fee for parking on Saturdays, Sundays, or national holidays. Be aware that the upper lot, off Davies Place, is only for commuters with passes during the week. However, if it's a weekend, all spaces are available to anyone.