My opinion is that would be a waste of money, particularly if you don't know how to master. Buying Ozone would just give you a set of processes that you might use most often while mastering (EQ, compression, reverb, stereo imaging, and a limiter) in one plugin or individually. I only own the silver bundle + a few from Waves and can adequately mix or master with them alone. I also use Alloy 2 in place of Ozone sometimes and essentially go through the same processes I would with Waves plugins. Ozone does have it's own benefits like having a lot of presets to get you started, but so do the Waves plugins.
For Waves plugins I find most useful with mastering, Rcomp, L1 Limiter, and S1 Stereo Imager. Everything else I commonly use is a stock plugin in FL Studio.
Lastly, don't underestimate the utility of stock plugins