What's the best (cheapest but legal) way to get either/or Adobe Photoshop/InDesign and/or Illustrator?

I use these programs at work but I'm interested in getting copies for personal use. I'm not sure what the best way to go about procuring them is. I'm not interested in illegally downloading them, either. If anyone knows of an open-source one-off that's reasonable, I'd be interested in that too.What's the best (cheapest but legal) way to get either/or Adobe Photoshop/InDesign and/or Illustrator?
You can buy cheap and legally, so as I do.

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