I don't know about cheaper but I am completing 2 tents 10 plants and have been using The One by true plant sciences. Use it in grow and bloom all liquid and includes the microbes. I do use silica which works well since it does drop your PH a bit and the silica brings it right up. I tried a quart used it up and decided to stick with it.
Was using mega crop but just too hard to get to dissolve and I still added microbes to the MC and this has the microbes included. I use 12 ml in veg and 10 ml in bud to get good deep green leaves with great frost. I am actually quite pleased with it, no tip burn a bit more cost than flora nova this is about 90 bucks for a gallon. The plants sure love it and easy to use.