My opinion is that spending more, if you're able to, on the headlight is worth it - but the tail light can be quite economical.
For front lamps, my experience has been:
SON Edelux: not cheap but absolutely worth the cost. Great brightness and beam pattern. Nice on-off switch. Looks great.
B&M IQ-X: i personally don't recommend, because it's most of the cost of an Edelux but nowhere near as nice to use.
B&M IQ-XS: i prefer this to the X actually, and it's cheaper, so this is a viable mid-range option to me.
B&M Lyt: cheap and not very bright, but if your headlight is mostly to make yourself seen rather than light up the road, worth considering!
For tail light, depends on your mounting options, I really like the B&M Toplight for its big reflector if you have a rack. If you want to fender mount, I used the Herrmans H-Trace tail light which is very inexpensive ($25 CAD or about $16 USD) and it's great.
It's also not unreasonable to run a battery tail light to allow you more funds to support a good headlamp, since tail light batteries tend to last longer. I love the Blue Lug Koma lights for this - they're small and attractive, and you can keep a spare in your bag in case the battery runs out mid-ride. Saves the hassle of running the wire to the back of the bike.