I look for ways to save money while maintaining quality of work and light stands are one way to do that. I have the Flashpoint Pro stands and they're plenty robust for regular use. You can see them on the equipment list on my website. They were about $40, not the cheaper $17 ones. If that saves you $30 each, that's enough to buy another modifier, weight, light mount.
You should be using sand bags regardless of what stand you have just as a general safety precaution, so stability isn't necessarily the core issue. Any stand on its own can be knocked over. Yes, C stands may be more stable, but if something blows over and you didn't have it weighted down, the type of stand is moot, and if you don't have insurance even worse. Any stand with a weight is difficult to knock over even in a strong wind. And if the wind really is an issue, consider not using large modifiers. Safety must come before the photo and sometimes sacrifices are made or the shoot is rescheduled.
Also, I like the air cushioned stands so if you unlock a pole without catching it the gear doesn't crash down. I do think there's a benefit to the C stands, but whether they're an absolute necessity depends on what gear you're putting on the stand. For regular stands, I think money can be saved. The Flashpoints are metal and realistically they'll take a good beating before you'd have to worry about replacing them.