More than a few people on this forum bought their Pacifica out of state at a dealer local to me in Ohio (Falls Motor City) because they could not find a deal as good locally. Some dealers do indeed advertise with discounts that only military members that just graduated college could possibly qualify for. Some dealers genuinely work on volume and truly advertise insane low prices that everyone qualifies for.
I bought my RAM used out of State in Virginia because I could not find a truck with the options I wanted locally, and the Virginia dealer (Koons) paid for a one way plane ticket out there up to $400.
Generally speaking, you are responsible for tax where you live, not where you buy. Most dealers know how to accommodate this, and will collect accordingly and pay your state directly. Many states also account for some form of tax reciprocity, and if tax was collected out of state, your local title bureau will likely only hold you liable for any local overage required if the tax collected and shown on the buyers agreement is less than your local rate. You may also have to pay a few bucks to get an out of state inspection of the VIN, which is something like a $3.50 required bit of paperwork here in Ohio.
2017 Pacifica Touring L Plus w/ Customer Preferred Package 25J - Built 11/2016
Advanced SafetyTec, Tire and Wheel Group, KeySense, 8.4 NAV, Wireless Charging Pad, Hands-Free Sliding Doors and Liftgate, 20-Speaker Harman Kardon Sound Group
2016 Ram 2500 Laramie 6.7L CTD Crew Cab, 4x4, Short Bed