What is this Phantasea excursion in Phuket? Can anyone tell me about it, where it is in Phuket and how much?

Lots of info on line. Check out
http://www.phuket-fantasea.com/glance.html

Phuket Fantasea is a large I guess you could day Diosneyish stled place, souvenir shop,s pay for photos and stuff, the main event is the show with Elephants and Tigers ( if they are still allowing ) on stage. Total tourist things ( not saying that is bad in any way ) as long as you realise it is totally 'that'.

Most tours take you there earlier than necessary, well perhaps so you have plenty of shopping time, many feel the buffet dinner plus show is not worth it, I agree with that though it is several years since I went though I was at their Grand Opening many years back.
If you have kids and you need some entertainment along those lines it's ok, but the show only ticket is the better way to go, the tour includes pick up in the 9/12 seater mini-vans.
But if you are staying in the Kamala beach area or Surin / Pansea ways then you might just as well make your own way to Kamala.
Most tour prices are usually absolutely 'the same' wherever you book, your hotel/resort desk will arrange for you, you can see the photos on their website which has been given, perhaps search on yahoo Asia for more comments to decide if it's your thing or not.

Without going into the 'value for money' angle as a straight out price it was expensive, luckily I didn't have to pay the 2 times I went, but localyy for say 2 adults and 2 kids it was just out of the question.

I will correct that comment on tour price, tour including tarsnfer and show sold localy should be about same price but unless you are there say Christmas or new year weekend no reason to book ahead.

I think it was around 1,800 adult and 1,400 for child, that is about USD 45 adult USD 35 child, so for a family of 4 that would be USD 160, or if you had teenagers USD 180.

A half day 4 hour Thai Culture tour including Muay Thai Boxing, Shrine Ceremony, Elephant show, Orchid Garden and lunch costs about B 750 ( USD 18.75 ) adult and B 600 ( USD 15 ) child.

I knowe they are 'different' but I would say if you can afford and it's a family outing then fine, you will enjoy, depends ages of your group really.

I was in Phuket last week, but didn't go to the place.

At the moment it is only open 5 nights a week due to low attendance. I read in the local newspaper that it will be open 7 days a week at some point in the near future.