There are many good recommendations (how many Watts per square foot), but I will emphasize something Mrs_Larimar said: “true watts.” Just make sure when shopping that you check what the actual wattage is and not the overarching manufacturer claim (can usually be found in the specs). Anything over a couple hundred watts will be fine for a normal sized grow tent and anything past the seedling stage, and you can purchase in the $100-200 range easily.
I have a similar light to this in my veg. and flowering tents (see link), full spectrum, and despite the claim it is actually in the 300-400W range. I recently damaged some young plants from light intensity by having them too close (within 15 inches) - i.e. The light is strong enough. I expect there is a range of more expensive brand name ones, and cheap no-name ones, but I expect most of the components are similar in each one.
https://www.amazon.ca/dp/B07HK8SWH7/ref=cm_sw_em_r_mt_awdb_FLMNCb9G1HACV