I apologize for bump...just my two cents.
You can drill holes in your roof if you don't want to spend the 100$ I don't think you can use the flood and spot beams separately. Wiring switches are simple a quick search on youtube should explain it. Also, do yourself a favor and run a quick bead of silicone around the bar to prevent moisture. They say they're watertight but a lot of times that isn't the case.
So far I have been using 2 brands ( Rough Country and Trail Master )
https://10carbest.com/best-curved-led-light-bars for all my light bar work and haven't had any issues with water etc. I have installed a few cheap amazon lights like your looking at and derian06 is spot on with using silicone to seal them up. It doesn't look pretty but it does keep them from getting moisture bubbles etc across your lenses. Keeping them sealed well also helps to keep them from "yellowing" creating a dull and reduced output. Currently, for the light bar setup for my roof rack, I have 7x 13.5" Trail Master's, 4x 2" square Rough Country and 1x 30" Rough Country X5. Rough Country makes some pretty night mounts so take a look at their website. There are a lot of useful videos on this subject on Youtube, I'll leave one here, Hope this helps.
https://www.youtube.com/watch?v=Imvj02eaU1M