how much does it cost for the underground tour.

About $15 plus tip

$15-$20 bucks for the basic tour. There are some other tour options available that are more expensive.

I like answering questions but this is one you can literally find on the website yourself

Last weekend it was 19.00 I think

That's the going price

I also recommend bringing some extra cash along to tip the guides. Ours was excellent and fully deserved it.

There are several different tour types available so you'd be better off checking their website directly or giving them a call.