Don't underestimate the potential of the slave market. You can easily sell back a "slave" for 10X what you pay in 10 minutes: Buy a lvl 1 slave for 600gp, grind him/her with 2 "seasoned" gladiators at the highest level arena you can win at a few times. After about 10 battles your new gladiator should be level 10 (depending on which arena you fight at) and you can sell him/her back for 7000gp.
I hate the fact that waiting in anticipation for the daily map ends in abrupt dissapointment when I finish the mission in 1:36...oh well, there's always tomorrow.
Buy NRG drinks early on and hoard them! It's easier to buy them on Star 3-4 when they are $8/11 bucks (you should have a salary of $7/8 per game and goal bonus of $2/3). Later on when the drinks are $17 and your salary is $12 and goal bonus $4 its much less affordable. Dont worry about leveling quickly either--best way to stall is to never pass off a goal shot...better to take it and miss than get the assist.
 "Sands of the Coliseum"){kind=icon}
 "Creeper World: Evermore"){kind=icon}
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