New to the industry

You could try using SFML, I'm a beginner programmer (the only language that I'm fully comfortable with is C) and I've been getting around in it with knowing the bare minimum of c++ lol .It also lets me incorporate C commands in my code which makes some of the game mechanics easier for me to code. Another engine you should look at is Allegro ( this one also seems noob friendly).

What language are you using? You said you know some 'C', but that you hope to learn an object-oriented language.

If your project is using C, I'd recommend SDL. SDL just released the alpha version of 2.0 which is stable enough to use.

If you don't yet know what object-oriented language to learn next, I suggest Python. You could use PyGame with it.

If you decided to learn C++, I second Randy808's good nod toward SFML. SFML 2.0 is available now.

If you are going with C#, consider MonoGame. All of these options are 100% free.

Most 2D games don't have common/shared 'engines' - the engines are kinda developed unique for each 2D game. 3D games almost always have an engine, but 2D games almost always make their own, but there are exceptions. GameMaker would be an example of a popular 2D engine - and is fairly flexible and powerful too.

Best of luck on your project!

(I should clarify that you can find dozens of free 2D game engines online - but try and see how many were actually used for any real games and not just example games. Most 2D games choose not to use an engine, or choose to make their own. I don't mean to imply that there aren't any to be found)

Oh yeah, allegro is very noob friendly for c++ programmer like me. I mean can you believe it loads all types of image formats with only one function? How about iOS and android support to put the cherry on the top? Cant go wrong at all here