Well I already do Photoshop on my little laptop. And maybe some gaming but not huge games if you know what I mean. Also, video editing yes. Which I also do some on my laptop.
Ok well if you feel you don't need great performance 600$ will do fine for just the pc without accesories. I would recommend getting a nice processor to start with and a ssd. Then you can add on a good gpu and more ram at a later point. Better to get a build you can upgrade then to get a meh build that you can't upgrade.