Best budget e caller for crows?

[Winchested]

Anyone have an opinion?

Do they make a amplified speaker for plugging into iPhone etc that is battery powered or rechargeable and loud enough to actually bring em in?

Figure it would be decent retrieve training for my dog rather than spending hundreds on pheasanta.

 

[Superbrad]

Ipod or mp3 playere with auxialliary out cable and a small radio or boombox boattery powered that has an auxilliary in....