I'd go for 2 of these, $36 ea
MKS
This is the MKS DS1210 Titanium Gear Standard Digital Servo. The DS1210 is a low cost water resistant, titanium gear servo that is well suited to surface and aircraft applications, and is an excellent choice as an upgrade for RTR and RTF models.
DS1210 Specifications:
Dead Band: 0.002ms (Default)
Control System: +Pulse Width Control
Working Frequency: 120Hz
(RX) Required Pulse: 3.0~5.0 Volt Peak to Peak Square Wave
Operating Voltage: 4.8~6.0V DC
Operating Temperature Range: -10 to + 60 Degree C
Operating Speed (4.8V): 0.15 sec/60° degrees at no load
Operating Speed (6V): 0.12 sec/60° degrees at no load
Stall Torque (4.8V): 111.79 oz/in (8.05 kg-cm)
Stall Torque (6V): 138.87 oz/in (10 kg-cm)
360° Modifiable: NO
Motor Type: DC Motor
Potentiometer Drive: Direct Drive
Driver Type: FET
Bearing Type: Dual Ball Bearings
Gear Type: Metal gear
Programmable: NO
Connector Wire Length: 15.0 cm (5.9 in)
Dimensions: 40x20x40.30mm
Weight: 56g (1.97 oz)
The closest thing from Hitec is the 645MG at $32 ea, but they are much slower, less torque and metal gear vs titanium for the MKS.
I have a few of these 645's and while they're not crap, they're not great either. I've broken the gears on 2 and had one burn out.
Savox is your best bang for buck, and these MKS look ok too.
Never tried the MKS personally, but they are are sponsor here so they might be good.
The savox one's to go for
$37.99
$39.99