Im pondering to build a granite park just like the old harrics park, only thing is im thinking of cost

does anyone know how much roughly 15 tiles of black granite would be in british pounds?

Also does anyone know where to buy the fake grass with flowers sticking out of them like in this video ? https://www.youtube.com/watch?v=367SLRVKEQo

im also looking to update my obstacle list im after weird but different things, anything anyone would recommend send me a link pronto! and keep your eyes out for the UK's version to the harries!    

Well, if your nice to the granite shop people, they usually will give you some granite for free! The granite shop i went to said they throw out over half a ton of granite every month.

at home depot for a 5 pack of 12x12 granite tiles ranges from around 15-30 dollars. it depends on what kind of granite youre getting. also if youre looking for things like mini bricks or fake grass check out http://www.miniatures.com/Default.aspx

A hobbie shop or art shop will usually have fake grass cheap!

The grass i see in all thw vodeos apears to be breeding grass dor fish tanks. It is hookes together in segments and can be cut for different sizes i used ro use it when i bred guppies as a kid to sale to the pet shop you can get ot at most petstores petco petsmart and walmart used to sale it when i was buying it. Flowers could be bought at walmart and just clip stems off...

Well it'll certainly cost you a lot, I'd say at least £60 I don't really know though, just me remembering last time I went to a tile shop, they do cost a fair bit though.
I beleive Harry Yeates knows something about the pricing as he made a park a lil granite park, I don't know if he's still about but if you can get ahold of him he should know, or I could ask him if you want