I tried out pole camping last weekend: the dutch forestry commission have a few sites where you can camp for free - no facilities, so you have to take in and take out everything with you. The sites are each indicated with a pole hence the name.
The website is here with the various locations, although it only seems to be in Dutch...
https://www.logerenbijdeboswachter.nl/paalkamperen
I went to the one at Austerlitz which is about 10km from Utrecht. Only down side, and it's a biggy, is that there was quite a bit of bog roll around left by previous campers. So gross.
The idea is that they're accessible for walkers and riders, so may be worth thinking about if you're on a tight budget.