Radians Pro Amp. $60 on eBay or at Academy sporting goods, $90 in your local BassPro.
Best ears under $100 in my opinion. Peltor's Tac 6 would be my second choice.
I do NOT like neckband-style because they aren't clamped on as tightly. Lying down on a 'bed' at a start, I've seen several sets left lying at the start position while the shooter departed.