best RC helicopter for beginner?

i was looking to buy an outdoor RC helicopter. It must be affordable and have 3d flight. i don't mind if it's petrol or electric

Depends on what you consider "affordable," also whether you want a kit or RFT (Ready to Fly).
MOST helicopters large enough for outside use start at $200 for "basic" units and go up from there, and may or may not include the necessary radio gear.