It's been some time since Used Trucks Dealership has been added to the game (1.49 if I believe), but are we allowed to buy Used Trucks in challenges? This will be an advantage for players, since they are cheaper.

It is an introduced game mechanic so there is no rule against using them. We discussed this in discord at one point, but realistically I believe it was not thought to confer any real advantage since you get the ability to get such a high loan so early, you can afford to buy brand new very quickly anyway.

But feel free to prove us wrong!