Batteries are a can of worms!

Traditionally most of us started out with Nicads which generally worked well and are still acceptable but getting hard to find. They can be fast charged, last for years and are very robust and tolerant of abuse. Nimh batteries are newer, have more capacity for a given size and weight of battery but they have their own problems, mainly lower voltage per cell, unreliable fast charge capability and not as robust as Nicads. Lipo batteries are newer and have their advantages but probably not suited for beginners because they are dangerous if not handled properly and will require the use of a regulator. Life batteries are the current rage because they can usually be used without a regulator and are safer than Lipo batteries but like lipo batteries will require a special charger and handling. Best to leave the lithium batteries alone until you gain some battery experience.

If using Nicads get a 4 cell pack of at least 600 mah capacity. If Nimh batteries get a 5 cell pack of at least 800 mah capacity. Either of these packs will give you at least enough power for about 2 hours of "ON" time or about 6 flights with reserve and without charging in between flights. Either of these batteries should cost under $20.00.