The price to have a basic arena built within your city's walls is 8
million gold. A standard arena is 40 rooms and allows Duels.

The prices to add other arena games are:

Free-for-all: 4 million
Team FFA: 4 million
(If your arena already has either FFA or Team FFA, then adding the other
only costs 1 million extra.)
Bait the frog: 2 million
Freezetag: 2 million

Please contact your city patron to arrange the purchase of an arena or
add-on game. Note that arenas belong entirely to the city that purchased
them, and individuals who donated to the cost of the arena aren't
entitled to any claim or privilege over the arena (except those granted
by the city, of course).

-Varian

Penned by my hand on the 10th of Severin, in the year 133 MA.