Unless you moved into a house with a grow room already there, spending $100 and putting plants under a light does not mean you have a grow room.
On my first real grow I spent about $1200, that included:
2 600 watt lights w/hood
6 in cabon filter
6 in exhaust fan
6.5ftx6.5ft grow tent
30ft of ventilation ducting
r/o filter w/reservoir and watering wand setup
A nice mister for foliar feeding
soil, pots, nutes and stuff for compost tea, air pump for tea brewing, 12x clones
I think that was everything. When I was younger I put some plants in a closet with a light, but that is not really a "grow room".
I could have shaved maybe a little off my total if I had shopped around a little more, or looked for sales, but for the setup I got, for the money I spent, it would be hard to do much better.
After all my first grow with that setup yielded 2.4 pounds of VERY nice GDP.
On the left, the described grow room in week 5 of flowering, I think the cola close-up was taken about the same time.