Anywhere between 138.49 to 399.99 (400)
$3.00
It depends on how much you build
The most expensive Lego set ever was the Lego set number 10179 ultimate collectors Millennium Falcon which originally sold for $500 on Lego.com.
Lego Indiana Jones sets typically cost ~5-30 U.S. dollars.
2000000$
It is most likey to be $12.99
The retail price for Lego Mindstorms currently is varying based on the size of the set. The average set costs anywhere from $500 to $800, depending on if it is new or used.
Lego Indiana Jones is in only $35.00 and it comes with a whole set. Get it now it's amazing:) At toys R us!!
There are two Lego City kits that have exactly the same amount of pieces and are the largest. These sets are the Garage and Police Station consisting of 953 pieces, these both cost 99.99 USD each.
Due to it being a retired LEGO set, you may expect a price of around $200 for it. You may be able to snatch a better deal though.
The best place to find the Lego Monorail set is on eBay. These sets are quite expensive and cost over $150 each. There are also many listings for parts for the Lego Monorail set on eBay.
Depending on what set you would like to buy, it can range from $25 to $250 (the latter being the LEGO Duplo Thomas & Friends - Thomas Load and Carry Train Set). I'm sure your kid will enjoy that one! I know I would have.