The cost of the meter to properly read LED light levels is usually cost prohibitive for home growers. I looked into buying one a few years back and a starter one was around a grand. However if you live in or near a large city there are sometime camera stores that have them for rent as even some pro photographers find them a little too pricey to own. My info is dated and tech changes rapidly so maybe there's a cheaper choice now but unless you're doing a bigger scale commercial grow you aren't going to need a PAR meter for a 4X4 tent home grow IMO. Get the data for your light from the manufacturer for a starting point, read your plants for signs of bleaching or light stress and keep an eye on leaf temps with a cheap infrared temp gun at the canopy. Best of luck with it.