Reddit mentions of Imperialism the Highest Stage of Capitalism

Get yourself some Chomsky, Hobsbawn, Foucault, Zizek and obviously if you haven't already, some Marx, Engels and more so some Lenin. Everyone and their granddaughter needs some Lenin.

The more you read and absorb the better you'll be versed in proper Socialist and Communist theory, which will in turn allow you to not only defend yourself against the imbecilic mouthbreathing conservative dumbshits that will inevitably spew 'Capitalism won cuz the USSR fell and, uh... Free markets! And...'Murica! And... Freedom!', but the more you'll be capable of applying what you learn to the world around you and acquire a more critical view of international relations, the global financial situation, the social makeup of society and of course the ramifications of your country's contemporary domestic and economic policies.

If you need some titles, you can't go wrong with Imperialism: The highest stage of capitalism, State and Revolution and Origin of the Family, Private Property, and the State

Read Imperialism by Lenin. I'm a high school student myself, I read this in about three days. Absolutely fantastic read and provides a fair introduction to the fundamental flaws of capitalism.

Books I would add to balance this list out:

Anthropology

Cows, Pigs, Wars, and Witches by Marvin Harris. Unlike Germs, Guns, and Steel, this book is written by an actual anthropologist (sorry Mr. Diamond) and is a really easy read--it covers topics from the sacredness of cows to cargo cults. It's fun, too, as Harris is an entertaining and engaging writer, and it's a slim book.

Bonus Level Challenge Anthropology Read:

In Search of Respect: Selling Crack in El Barrio by Phillipe Bourgois. This is another monograph written by an actual anthropologist. This book is more challenging subject matter, and I should put a big Trigger Warning on it for violence against women.

Economics

Wages, Price, and Profit by Karl Marx. It's a shame more people don't read Marx beyond the Manifesto, which he wrote fairly early on in his academic life. W,P and P is a preparatory work for Capital and outlines one of the arguments Marx makes in the much denser and more complete work that was to follow. It's short, and one of Marx's more approachable writings, dealing with something we are all familiar with: how much we get paid, and why.

Bonus Level Challenge Economics Read:

Imperialism: the Highest Stage of Capitalism by V. I. Lenin. This book contains much drier material, as Lenin draws upon common economic sources (I hope you like talking about tons of iron) to illustrate phenomenon like World War 1--which he saw as a competition of imperialist powers to redivide the Middle East and Africa--and even the Iraq Invasion that would come almost 100 years later.