Reddit reviews Young Justice: Dangerous Secrets

Here is Season 1 Part 1 on the Canadian Amazon (CDN$18.74)

Here is Season 1 Part 2 on the Canadian Amazon, but says [Import] so it is likely the US one (if that matters). It is out of stock at Amazon, but third part sellers are selling it new starting at CDN$20.47.

Here is Season 2 Part 1 on DVD on the Canadian Amazon (CDN$11.48).

Here is the Season 2 Part 2 DVD on the Canadian Amazon (CDN$13.88).

While these aren't necessarily cheap, they really aren't that expensive either and you get the entire series on DVD. That being said, you may want to think about investing in a blu ray player or current gen game console. DVD is likely going to be a dying breed at some point in the future and blu rays usually have much better quality.

The first half of season one is here and the second half is here, bringing the grand total to just over $1.01 per episode and only taking up 2 DVD boxes worth of space.