I compared the prices of the campsites...
All prices per night
1)
http://www.seecampwallersee.at
$9.60 for unit + $8.35 per person
--> $11.55 p.p.
2)
http://www.camping-vierthaler.at
$17.16 for unit + $5.13 per person
--> $10.85 p.p.
3)
http://www.camping-kasern-salzburg.com/
$21.48 for unit +$5.96 per person
--> $13.12 p.p.
4)
http://www.campingaigen.com/
$16.45 for unit + $5.72 per person
--> $11.21 p.p.
I hope everything is correct. If you want I'll make a reservation when we've a favorite one.