This. I recently left Santiago headed north with all of my camping gear. I try to stay in inexpensive hostels whenever I can, but I have camped a few times. Generally "camping" in Chile means having access to hot water showers and a pool, but just sleeping in a tent. This means that camping in real campsites here is not cheap.

If you want more specific details, here they are. Between Santiago and La Serena is a small beach town called pichidangui. Right after the exit from Ruta 5 is a recreation area, which is a series of dirt roads and trails. Actually quite fun to ride around in on a motorcycle, but also where I spent my first night camping for free. There was no sign saying it was OK to camp here, nor was there a sign saying it wasn't. Either way it was free and no one bothered me that night.

From there to La Serena was easy and there are a couple good hostels there. This is where it got tricky. I was planning on hitting the two national parks between La Serena and Antofagasta, spending one night camping in each. Unfortunately an electrical issue with my new Honda forced a trip to copiapo. I spent that night in the small city of caldera since the one camping option I found in copiapo was 14,000 Chilean pesos... After Caldera I spent two nights camping in pan de azucar national park, at a cost of 4,000 a night. There is a beach before the entrance to this park that would be perfect for guerilla camping if you would prefer. Past Antofagasta things really open up. If you're brave there are hundreds of small dirt roads and trails branching off the highway, some of which even lead around or over small hills if you don't want to be seen from the road. I spent two nights camping in the desert for free with no problems.

I'm in a great hostel in Iquique now and have been moving very slowly if you catch up and maybe need a riding buddy. As far as going up Argentina, someone else will have to chime in with details, but I've heard there is more free camping there. Just be careful with the passes this time of year. Let me know if you decide to come up through Chile and have any other questions.