Hi this is what I think are essentials for a successful grow.
On my first grow to run 4 plants I purchased a 80 x 80 x 160 tent
A grow light whichever you chose just make sure it has the power you need and can cover the area you are using
Mixed flow extractor fan and ducting to suck stale air out of the tent
Carbon filter
6inch clip on fan
PH and EC meter
Temperature /humidity meter
Whatever medium you plan on using (soil/coco coir)
You don't have to spend a fortune on your first equipment but it is really important to get the environment controlled and be able to monitor the ph /ec or that will just cause issues for you from the start.
There is lots of really good information about growing you own on here and if you have questions someone will generally help you out.
I love growing my own meds these days and I have bought a bigger tent and updated my light to LED and bit by bit I have updated my equipment but it took me a while buying bits whenever I could afford it.
Get yourself some decent seeds for your grow have a look at the information about any seeds you see that you want to grow as some are easier to grow than others and ideal for someone who is doing there first grow I would suggest that you consider buying fem seeds as you don't have to stress over the sex of the plant that way not on your first run anyway
I really hope this has helped, best of luck with your first grow