If you don't want to abide by the LGPL requirements you will have to fork out 459 USD a month. For an established development company this is not a big deal, but for a side project?
If you know the difference, then why did you claim it requires you to license your code under GPL? You can use Qt and other LGPL libraries from a proprietary, closed-source code base if you wish, no license fee required. LGPL is a lot less onerous than GPL.
LGPL is mostly a problem on iOS, since as far as I know it collides with App Store licensing rules, but not that big a deal on desktop platforms.
If you don't want to abide by the LGPL requirements you will have to fork out 459 USD a month. For an established development company this is not a big deal, but for a side project?