Try the Planet Bike Superflash for the taillight. And preferably more than one of them. They're not perfect, but they're pretty good.
For headlight, can't help much. You don't want "bang for the buck" you want "adequate to see". What that is depends on your vision and your riding conditions. I use a hub-generator setup, which is great for my applications, but that light can get washed out by bright car headlights, so it may not be great for yours.
__________________
"be careful this rando stuff is addictive and dan's the 'pusher'."