1 TFG is approximately how much do you think in satoshis once you launched the mainnet? somehow, you need to think of a base price once you launched it. and also, to create game account, you need to pay 1 gold fee. is it readily available to purchase? maybe, you can also add that in your faq, how can you deposit the TFG to create the game account? and where are you going to purchase it?
It's really hard to say, but a possible indication is that since the emission curve is the same as Monero, scaled by 2 IIRC, then if you consider it might be valued at 0.1% of Monero for its market cap, it'd be... $250 / 1000 = 25 cents. Of course it's kinda circular reasoning since this number relies on estimating the market cap to be worth 0.1% of Monero's, so it could be $2.5 if you think it should be 1% of Monero's, or 2.5 cents if you think it should be 0.01% of Monero's

In the end, it'll be whatever people in general think it should be.
To get gold, you either mine it or buy it. It might or might not get added by an exchange, but if not, I'm sure people will offer P2P exchanges. Once you have some, you just click on "create account" in the game, and fill your player name and how much to deposit. The fee will be taken on top.
I imagine the first few players will just fine some to start with.