If you’re ready to take the plunge into LED lighting, this 6-pack of bulbs from TCP is down to just $10 on Amazon right now in both daylight and soft white temperatures. They aren’t dimmable, so you won’t want to put them in certain fixtures, but they’re great bulk packs for the price.
Once you’ve got them, check to see if your local utility company offers rebates for purchasing LEDs. If so, it’s possible these could pay for themselves even quicker than they would otherwise.