My budget is $750 and the tank is mixed reef with dimensions of 39Lx20Dx20T so I think two primes would do the job for my budget, but I am open to other options.
I just got back into the hobby about a year ago for LEDS are new to me.
I think with it being 39x20 footprint 2 primes will be very low light (I've had a prime before). You'd probably get away with a mostly softy with some LPS on top with those.
Personally, I would go with three 35 inch quanta-helix bars ($200 each) and you can mix and match them. If you like more white, get 2 white and 1 blue, or vice versa if you prefer the blue light. They can also be turned down now... and if you grow in a ton of corals or decide to go SPS, you can always add 1 more, or just go above your budget and get four right away. The ReeFi Pros you'd need 2 just because its 40 inches long (but you'd have them turned down half way). They would also put you closer to $1000, but those are fully controllable, you can set the schedule and whatnot.
Check out both and read about them.
Quanta Helix
ReeFi Pro
If you search around the forums, these are less known brands because they are a small operation (each is ran and operated by a single person that is highly invested into making reef lighting affordable). And you'll find both have crazy good warranty, customer service, and the lights punch waaay above their price.