You get much longer run times and brighter lights with 18650 batteries. They are higher voltage than AA which gives you more light. They hold more energy which give you longer run times. You'll read lots of opinions here, but 200 lumens isn't much light. If you are going to ride at night a lot or for long rides I recommend 18650 and a $100 budget.

Shiningbeam brand lights are excellent. I recommend a P-Rocket XM-L (850 lumens) on the bar and a XP-G S-mini for the helmet. The Xtar WPII charger is $20 on fleabay. 4 batts will run you $25. You'll have enough light to ride on the darkest MUP. I really like the helmet light for looking along the sides of the MUP where the critters are always hiding.