Good! Glad to have been able to help.

Just one extra correction: 

1.    Slang is very informal language used amongst the members of a particular group of people (  ethnic or class group/ an age group/ a profession / sports supporters etc)  "Quite a penny or two" is not slang - it's just a phrase.

2.   You can't say 'this slang'.  The word 'slang' is an uncountable noun or an adjective, so you would have to say, for example, "What does this slang expression mean?".

I hope that's useful.

It’s just means expensive. -->  It just means expensive.

@Serg:

SHL is right. This expression means 'It is expensive'. If you said 'It's just a penny or two', that would mean inexpensive.  However, 'Quite' signals that there's probably an understatement coming up. For example, "It costs quite a bit" actually means "It costs a considerable sum".  Remember that English loves understatement - especially BrE!

British understatement  is a bit of a problem for everyone.

A friend of mine is a world expert in VPN design and went to a LA conference where someone asked him if he knew anything about VPN design.

"I dabble" was his answer (which would appear natural to a Brit and means "I'm pretty good") but in international English means "I play with it occasionally"

So the questioner walked away from talking to a world expert.

I haven't heard anyone say this for years, but what I heard growing up was

"It cost him a pretty penny."