Check your local craigslist for some used equipment.
I'd focus on setting up the rooms correctly the first time. Even if that means you slowly work your way to that 8x8 space. Build your veg room, an finish a cycle in their. Then put all the money from harvest into flower room.
I agree with you, having a veg room and a flower room would be great. But for a budget of 600 dollars I just don't see how this is possible, if you say "do it right". To include all the nutes, grow mediums, wood to build the room, screws, pumps and hoses, measuring materials, ph meter, ppm meter, thermostat, fan and filter. Done right and done budget is just 2 far apart.
