Hi Donna, Outdoor kitchens end up being a bunch of money. I own a construction company, get all my materials at wholesale, got my 'guys' to do the work for me at their base rate...and it still was a lotta dough!
Some of the "X" factors are: getting gas to the kitchen (getting more than a 1/2 inch pipe run and making sure your meter has enough flow), electric (with breakers and underground wiring, and no overloads on circuits...because usually the outdoor kitchen will be added on the 'end' of your house and electrical runs, or else you have to run a whole 'nother circuit), water (and I didn't even tie in to sewer...my sink drains to a five gal. bucket that I dump), concrete work for the 'pad' and of course running all the utitilites under concrete to get them to the kitchen.
I built mine out of metal 2x4's, cement board, and then stuccoed the outside, and put travertine tiles on top. It is in the most technical of senses "moveable" though way to heavy to move (i.e. not bolted to the ground).
It has a grill, double side burners, a small sink, storage and a small fridge. "L" shaped with plenty of elect. outlets, and 'stand around' room.
Grill was $3,000, 5-7 hundred for the sink, fridge, and door panels, 5-6 hundred for the materials and a couple thousand for labor. Kicked the heck out of $10,000 by the time I was done...at 'wholesale.' (also put in a fireplace at the same time, but that was a whole 'nuther 10 grand)
So, long winded, but pretty easy to spend $15,000 on an outdoor kitchen. Materials play a bit part of the cost, too...stone veneer, lighting, waterfalls..etc.