Update: Challenge mode on Darts is very good! Challenge mode costs 2500 tickets. Difference between challenge mode and single player darts is the amount of tokens/tickets you can get and the board moves but not the bulls eye! Depending on your score, you can get 6-10 tokens!
You can get tokens from playing the games that don't cost tokens (slots, disk-o, stop light). I was able to get 5 tokens everytime while playing darts; it seems like you need to get a minimum of 400 score to get 5 tokens. There's a perfect spot to get bull's-eye everytime! Move the crosshairs to the middle of the board then throw it around 46-54 power. Depending on where you placed the crosshairs , the power may vary. It also only takes about a minute to do!
Still trying other ways getting tokens. Bocce ball and cornhole is okay for tokens, but longer