To get some extra money for better performance all you need to do is tap the money + and then tap watch ad for $1000 . it's not a lot, but you can watch enough ads to get enough money to make your truck good enough to win the races. The winch can be your best weapon for getting through some very nasty stuff with little to no problems, it's all in the timing and the view from directly above is the best way of seeing over an obsticle and getting a good anchor point for the winch hook.

You can't as far as i know, but the game is still in it's development stages while all the bugs get worked out. You can get $1000 for each video you watch and you can watch a lot of vids every day to get a huge amount saved up. I'm sure once gigabit figure out the bugs, they will add more vehicles and the option of entering codes.