You'll do fine if you follow Nebs advice ,on here.
Study up on training, helps your yields tremendously.
For 4sq. ft, a good light would be any decent quantum board like Hlg, or similar,
You want about 30-50watts a sq. ft. to grow decent bud.
If you get a QBoard with about 150watts, you'll do a fine job.
In my little tent 2x2x4, I use a HLG100, and it does ok, the lights not but about 150bucks.
You can grow some fine bud in that little tent, for cheap.I love my little tent, anywhere from 2-3ozs, to 7-8 ozs, in 2-3 months, like clockwork. I doubt I'll ever use my big tent again, unless it gets legal in my state.
Good Luck growing ,it's fun an addictive.