Netherlands
If I had to choose just one place as my absolute favorite trip, I would have to go with the Netherlands! Normally, when I plan a trip, I research forever to find the best places to go. Then I research some more, then over-research. However, the Netherlands was a trip that I booked immediately after hearing from friends about what there was to do there. The Netherlands just has to be experienced! I highly recommend going in April, because that is when the famous tulip fields are in full bloom (full season is March through May).
Recommendations: (Actually I'm going to call them must-do's).
You must book a bike to experience the Netherlands. The whole country operates on bikes and there are dedicated bike lanes throughout the whole country. We used www.lemonbike.nl, based in Noordwijk, where you can choose from e-bikes, motorized scooters, road bikes, tandem bikes, etc. Book early if you want to get an e-bike, though. We didn't book early enough, and the only thing left were regular road bikes, which actually were still nice. Very smooth riding.
You must ride the Flower Path. This is a 22-mile path that goes through all the gorgeous tulip fields. Instagram worthy shots all afternoon. Then follow that flower path all the way to the North Sea. Here you can enjoy some time on the beach, get some ice cream, drinks, etc.
You must stay in Eurocamp in Duenrill. $100 per night gets you a 3-bedroom house (you need to bring your own towels and linens, or rent them for a fee). This fee gets you not just your accommodations, but your entertainment at the on-site theme park as well. There are tons of rides for teens and kids alike, without the price tag of the theme parks back home.
You must experience Keukenhof. Some might argue that this doesn't fit the bill of a budget-friendly activity. If you stayed at Eurocamp, you have already saved on everything else. Splurge on this activity. These are world-famous tulip gardens that are unlike anywhere else I have been. Avoid weekends and go first thing in the morning when the park first opens though, as people flock here from all over the world and it can get crowded. We arrived on a Monday morning right when the park opened and enjoyed it crowd-free.
Other recommendations for frugal family fun.
Delft, Netherlands. Free. Just a 30 minute ride from Duinrell is the quaint town of Delft. Fabulous cheese stores, porcelain stores, markets, beautiful canals, promise an exciting afternoon.
Clara Maria Cheese Farm & Clog Factory. Free admission. This factory will show you how cheese and the well-known Dutch wooden clogs are made. Enjoy cheese samples as well.
Corrie Ten Boom house. (Author of The Hiding Place). The admission and tour is free, but donations are welcome. Here the Ten Boom family risked their lives by hiding hundreds of people wanted by the Nazi party, before being arrested. Must make reservations in advance.