High voltage Endurance motors for cheap is correct they are cheap like 20$ or so some of the motors are obviously branded so are been rated high am going to list down 3 motors i found to be better in efficiency and are good for endurance long flights.
Visit here for long time endurance flight quadcopter build : LINK
Motors :
SunnySky V3508 380kv
Racerstar Racing Edition 3508 BR3508 380KV 3-8S Brushless Motor For 600 700 800 RC Multirotors
Multistar Elite 3508-268KV High Voltage Endurance Motor
You can click on the motor names and check the specs although you can also scroll down i have copied them for you.
Now coming to individual price which is very important.
SUNNYSKY is a brand and they make awesome motors but they have a lot of oem and fake manufacturer in the market so buying from china from sites like aliexpress or ebay can land you with fake knockoffs beware. You can directly buy from sunnysky talk to them. Price for sunnysky is about $37.9 on Getfpv which is i feel costlier than the other 2 motors.
RACERSTAR is the best motor i felt among all the 3 due to the price and the datasheet i would say datasheet of all 3 motors is almost the same with some 0.xx amps here and there but it doesnt really matter as that can be counteracted with many other factors and tricks. Price of this motor is just $15 with free shipping on Banggood which is nice and best in the budget it runs on 3s to8s which is again a good thing.
Now the final motor which is the Multistar elite 3508 268kv now this is the motor which can be optimised and is a bit pricer than Racerstar Hobbyking has given us various specs and types of configuration for the same so that we can arrange the configuration between hexcopter and quadcopter and 6s and 8s battery according to our needs. This motor costs a normal customer $34 and for new or diamond customer about $24 which is $10 difference.
Best motor to buy if you are on budget and want to try a brand out go for Racerstar v3508 380kv only for $15 .
Now that is just Rs.1000 for each motor which i feel is nice also the weight consideration of this motors comes out to be cool.
DATASHEET
SUNNYSKY
MULTISTAR ELITE
Multistar 3508 268KV @ 32V (8s)
12.5×6 50% 800g 4A 100% 1200g 7A
13×3.8 SF 50% 580g 1.5A 100% 1320g 4.9A
13×4.7 SF 50% 620g 2.2A 100% 1410g 5.2A
13×5.5 C 50% 670g 2.7A 100% 1600g 6.8A
14×4.7 50% 710g 3A 100% 1460g 7.8A
Multistar 3508 268KV @ 25V (6s)
14×4.7 50% 598g 2.4A 100% 1030g 5.6A
15×5 M.S.W 50% 712g 2.8A 100% 1144g 5.8A
A 680mm Hex such as the Tarot or 680UC pro Quanum AUW with battery and gimbal weighs 2.5~3.2Kg @ 3Kg/6(motors)=500g lift needed per motor to hover.
Hover efficiency 3508 268KV @ 32V (8s) 500g thrust x 6 =3K
12 wood 1.96A
11×5.5 APC speed 2.3A
13×3.8 sf 1.5A (X 6= 9A hover)
13×4.7 sf 1.6A
13×5.5 C 1.6A
13×6.5 APC 1.9A
14×4.7 sf 1.4A (X 6= 8.6A hover)
Hover efficiency 3508 268KV @ 25V (6s) 500g thrust x 6 =3Kg
15×5 Multistar White 1.7A (x 6=10.2A hover)
14×4.7 SF 2A
This sub 10A hover can allow the use of high density low discharge batteries. The increased capacity vs weight will increase flight time. Flights over 1 hour are possible with special batteries such as the Panasonic 18650 or GEB cells.
check out this link for full build information for endurance quadcopter.