Champion Sports 8 Watt Megaphone
As I mention elsehwhere on this site, the fact that a megaphone is branded as a "sports megaphone" does not mean it is any different from other bullhorn megaphones. This is often a marketing gimmick to catch your eye when shopping for a megaphone to be used at sporting events.
Sales parlance aside, this is a well performing megaphone for the price. Given the price mark here (around USD$40), you can amplify your voice over many hundred feet when background noise is a minimum. However, with increased background noise and interference, the carry of the amplification starts to taper off significantly. If you are focussed on a small area with minimal background noise, and you are looking for an entry-level megaphone, this is a very good choice.
This model has a built in siren for attracting immediate attention. It is worth noting, however, that the megaphone has no volume control built in for the siren. There is sufficient range in volume control for voice amplification, but the siren is a "one size fits all" type, so you could end up upsetting those nearest you if there is low background noise!
Battery life here is adequate, giving around 6 hours when I used it continuously. Of course, battery life is something that impacts all bullhorn megaphones, and 6 hours is a pretty respectable life.
Others who have bought and actively use this model claim that there is little to no feedback associated with the microphone position, which makes it suitable for ad-hoc usage and quickly projecting your voice at short notice. If you are sitting in a booth and using a megaphone, you could perhaps look to a sturdier model with better amplification, but for those who need a portable, occasional megaphone, this is a very good investment.
If you are looking for more information, or to purchase the Chamption "sports" megaphone, Amazon offers it (among with some more user reviews): Champion Sports 8 Watt Megaphone.