Most people (especially small indie devs) will be fine with the free LPGL version, regardless of whether you charge for your software or whether it is open source or not. Just make sure that you dynamically link the Qt libraries (so the end-user can theoretically replace them if they want to) and don't use any of the GPL-only add-ons (unless you are OK licensing your whole product as GPLv3).
I knew someone would bring that up! Yes you can statically link but its harder to go that route and probably not worth it for most people (although for some platforms like iOS you might have to, not sure about that).
I've used Qt for over 15 years and I've never once wanted/needed to statically link it since dynamic linking has always worked just fine for the type of apps I've worked on.
