That is an extraordinary amount of money OP.
It is very important that you do your own homework.
Price the EXACT tiles you want.
The shop should be able to tell you approximately how much base and grout you need.
As the area is mostly prepared, you could ask the shop of an idea how long a job like that might take.
Get proper quotes with a full breakdown of cost and the time it will take.
Don't be tempted by cowboys.
Do you know anybody that got the job done well?
Wait for the right crew.
Research is key.
The more you know about the job you want done, the less likely you are to be ripped off.
Rushing to get it done by a cowboy will be something you regret and crap workmanship devalues a home.
Take your time, do your homework and get the right person for the job.
There is no reason why you wouldn't buy the tiles directly and have them delivered.