It's true, you can use a basic plastic funnel your whole life if you want or need to be frugal. People were making very good ammunition 75+ years ago with what was available then. If I were to measure the time spent fiddling with kernels of powder, especially spherical powder, clinging to the plastic funnels as well as factoring in the associated levels of frustration over the last 25 years of my reloading, then apply a monetary value to my own time, the $100 on a frustration-free funnel set becomes an absolute no-brainer. If your plastic funnels aren't causing you any frustration and you aren't able to determine that you're wasting a measurable amount of time by using them, then that's great and you can save that $100.
In all honesty, if you spend much time reloading at all, it probably wouldn't take very long with a modern funnel before you'd think, "oh wow, this actually is a lot less annoying!" Whether that would be worth the money is all up to you though.
