The first place I will go is Kalmar castle in Stockholm.
The second place I will go is Örebro Castle in Örebro
Reasoning
The reason that I want to go to these castles is because they are the number one and two on the best tourist attractions. Also I think castles are really cool.
Price
The only things that would cost anything is if I got a tour so I am only going to budget $50 for gas.