The first larger crypto currency exchange to enable support for deposits (address generation) as well as trading of the new Bitcoin Gold (BTG) fork is HitBTC. Trading markets for BTG are available for Bitcoin, Ethereum and USDT, though the BTC market is the largest one with almost 2000 coins volume in no time. The current exchange rate of BTG is about 0.025 BTC per coin or about 150-160 USD, so lower than the initial trading before the actual Bitcoin Gold network went online. At the moment there are still not a lot of BTG coins available on the market due to the fact that most users still haven’t claimed their Bitcoin Gold coins they got for holding BTC in their wallets, so that can cause initial spike in price back to higher levels until more coins are available. Although the initial start of the BTG network was a bit slow and not without issues now things are apparently getting normalized and we should soon see more exchanges adding the asset for trading.