Do your self a favour and get a day pass and use the tolls. It is cheaper and less stressfull in the long run. Our Tom Tom (with a male voice) has paid for itself on many occasions. A friend of ours has an "el cheapo" brand and on one occasion he ended up in a deadend Sydney street. The end result was a 400m reversing exercise with a 21ft van attached. He was not a happy caravanner.
Victon 2, don't throw it out the window you may hit some one and you will be in more strife.