Simple Asset Protection

Hello everyone! I am finally nearing the end of the game I am making with Torque 2D. Most of the 2D art in my game was created by taking top-down print screens of models downloaded from TurboSquid. I created the menu art myself.

Of course, I know you can't make a game crack/hack proof, but I do want some simple asset protection. The main reason for this is because TurboSquid's policy requires such protection of assets. Also, I don't want to give amateur hackers the ability "easily" go into the game's files and modify whatever they find. I want to make them work for it. :P

Another reason I would like protection is because the player's progress save file is saved in plain text, since I don't know how to mod the engine to save encrypted/binary files. I know how save files like this in C++, but I don't feel like trying to figure out where in the engine's code I need to inject this functionality.

So my question is this: what are some good tools out there for asset protection? I plan on releasing this game for free and I have already spent money on the engine and the music for the game. So I would prefer a free protection tool, but I am open to paid options. Please let me know.

Thanks