Limited budget, I can relate!

I use a Planet Bike Superflash on the rear (awesome!) and a Planet Bike Blaze 1-watt headlamp (I had a half-watt Blaze, but it didn't throw out quite enough light for me).

I'm all about visibility, so I've also added a Spokelit light on the front wheel, and some of those cute reflective stickers TE has on their website (on the wheel rims, on the seat stays, and on my helmet). Top it off with a reflective jacket or vest, and you're good to go!