I have a budget of 600 and I'm not sure what to buy first, or what to spend a little extra on. I already have a monitor keyboard and mouse. Any suggestions?
Gpu should be the biggest investment. You could get a i3-4xxx, a h81 mobo, r9 270x or 270 for about that budget. Make up a basic build on pcpartpicker.com with that and post a build help or build ready post
/r/buildapcforme can help you out here.
What are you thinking of doing?