My favorite vacation I ever went on was to the Oregon Coast. We camped on the side of Upper Klamath Lake, I took photos of a Great Blue Heron fishing not 6 feet from me at dawn. We went to Crater Lake, drove over the Cascades and Coastal range, camped right on the beach by a private cove not far from Coos Bay. The fog rolled in at night and visibility was practically zero on the beach as the ships horns bellowed, we went Agate hunting at low tide at Bandon Beach, and brought almost all of our food. We cooked on my camping grill and ate homemade tacos on the beach. On the way home we stayed in a cheap basement AirBnB in some tiny town. I don't know how much it cost in total, but it could've been half as long and still been amazing. 

I'm sure I would've liked eating at a restaurant or staying in a nice hotel, but when I think back on that trip, the things that were highlights were all free.