For your budget the best thing I could suggest is
an Autocob
It will do you fine in that size of a tent and has a great PPFD for a 2x2 space. If you get deeper into growing you'll find that DIY or quality LED manufacturers will post
PPFD and or
PAR. This link explains all the terminology needed for understanding horticultural lighting as using
lumens is for humans whereas plants absorb photons so light has to be measured different.
Basic conversions of lux to PAR or PPFD exist but they don't account for the CRI - usually 80 to 90 on quality LEDs - which can effect the efficiency and output of PPFD. The best tool for measuring this metric is a PAR meter from Apogee however it is a $600 item. Second best thing you can do is read a manufacturers PPFD chart to get an idea of intensity and proper hanging height unless you have that meter.
Below are 3 different PPFD charts worded and displayed in 3 different ways.
The numbers denote the PPFD over a given height and space with averages.
Mars does the same thing albeit differently but in their case case they are offering averages at certain heights and in pre defined spaces
This is the PPFD chart for Autocobs and provides a general height/average umol - PPFD - and even provides info for reflectors.
Watts per sqft is a general guideline but not entirely accurate so your space would be recommended for 120 watts but a high 800+ PPFD for flower would be ideal and helps when looking for a light to cover a given space. It just might be less than 120 watts which is less power and more efficiency.
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