My new house comes with gx24q-3 bases and CFL bulbs everywhere. I read that LEDs are better in every way. I've found some br30 e26 LEDs for only $1.25 each at Costco. Does it make sense for me financially to replace my gx24q-3 base with e26 to use these cheap LEDs?
Most of the return on investment (ROI) evaluations I have completed have shown a positive ROI within 2 years 2 months for very expensive fixtures. When only changing the lamp the return is much quicker just a few months in some cases. But this is when relamping is needed. To go in and swap good functional lamps still has a positive ROI due to reduced maintenance and lower power consumption but wholesale swap of CFL to LED is not "green" due to the good material that is being disgarded. If new to you,,, not brand new it could be worth it as CFL life curves show less lumens as they age. If you are going to be in your home for at least 2 years it makes financial sence to make the change and after 2 years not having to replace the lamps, instant on at full brightness are additional reasons to change.
Whether it's economical or not depends on how much it costs you to replace the sockets and not just the cost of bulbs... and what time horizon you're looking to recoup your expenditure. (Off the top of my head, I would bother only if you plan to keep the house for 15+ years. CFLs may become difficult to source in the long run.)
There is alas no standard for how sockets attach to fixtures, so it all depends on what you have and what you can source and for how much. Detach one gx24q-3 socket, go with it to a local hardware store and see if you can find an e26 socket that can replace it (same number of screws and distance between them etc.) And indeed as Tyson remarked, the gx24q-3 fixtures have separate ballasts that need to be bypassed if you intend to keep the fixtures.