Yea, well - we do not know the prices for this kind of service. Can you, please, clear this for us ? Thank you !
$300 is more than enough money, but it's question wheter designer will accept your token or no. Mostly prefer to get BTC, ETH and other major coins. It's quite risky to accept tokens.
Some designers have public prices of their services, while others don't have fixed price. It depends on your needs - you want simple or more complex signature, for how many ranks signatures are needed. I recommend to open list of designers and try to contact them to discuss everything in detail.