I bought a used generator bottle last fall on ebay, to use with one of the 6v LED plastic headlights I got from Boygofast- and I already had another tailight- it works well, but I never ride at night and I took it back off for now-
I also picked up another NOS whole generator system for a beater pedal bike- I think I got it shipped all for 10 or 12 dollars- They used to be expensive on ebay, but the prices have come down with all the new LED gadgets out there- and new generator sets can be had for $20 if you loook
Some people say the bike is too fast- I dunno- didn't use it much, but maybe try to get a newer, lighter one- the newer bottles are miniscule- and supplement it with LEDs- otherwise
search "bicycle lights" on ebay and sort the list by shipping/ lowest price first- I've got blinkys for a dollar and a half and various kinds of LED headlamps- mostly to be seen- for just a couple dollars- only have to wait 3 weeks to come from China-
search "generator" too- it's pot luck- might be high prices in mid-summer. Dunno.
Got this platic LED white blinky this spring- it just clamps around the bars in 2 secs- very cheap. Carry it in your pocket.