New to the hobby, help needed

I am new to this hobby. I built a small grow box lined with aluminum foil. I have a 2' aq, plant flor. and two seedlings seem to be thriving. I just bought a HPS 70w bulb and need to find a inexpensive fixture. Also I have been having trouble getting the seeds I have to germinate. I had two do nicely but they grew to fast and the stalks were to thin and broke under the weight. Others have germinated but will not now break the soil. Any help appreciated.

Welcome to roll it up. Are your seeds from a seed bank or are they just bag seed? I dont know anything about HPS so cant help you there. I might as well say it before someone else does but dont use aluminum foil, it creates hot spots apparently, you want something white and reflective, you best bet would be mylar

how warm is your box

you want 70 degrees that will speed up the growth

Go to lowes or manards and get a yard light they have a 70 watt hps light with some work you can sperate the light from the ballast