Among the Mae Enga of New Guinea, 25% of male deaths are due to warfare. Mortality from war is 0.32% per year. Despite this, they can double their population every 25 years. [Raymond C Kelly, Warless Societies and the Origin of War]
Kelly's most interesting point is that almost all societies have warfare (or at least feud). Those that don't are unsegmented societies which don't hold members of a killer's group responsible for a killing. In a society with warfare (or feud), if someone kills your brother you can kill their brother and gain emotional satisfaction. In a warless society, you have to kill the killer.
Note however that warless societies may have high murder rates.
[Raymond C Kelly, Warless Societies and the Origin of War]
A much better book is Lawrence H Keeley's War Before Civilization; unfortunately I don't have specific notes from it.
Before the siege of Rhodes (304 BC), the Rhodians and Demetrius the Besieger agreed that a captured freeman could be ransomed for 1000 drachmas, a slave for 500 drachmas. A drachma was about 4.3 g of silver. [John Warry, Warfare in the Classical World, p.92]
Demetrius the Besieger had "a cuirass which completely withstood a catapult dart at 26 paces and was considered light, at a weight of 40 lbs (18.1 kg)." His lieutenant wore a panoply weighing two talents, though a more normal weight was one talent (57 lb or 25.86 kg). [John Warry, Warfare in the Classical World, p.93]
“Maintaining large cavalry forces in China was hideously expensive since, in the absence of grass, a horse ate about as much grain as a dozen persons. ... Hiring nearby steppe cavalrymen to guard the approaches to China was a far cheaper alternative. But that, too, could fail whenever such guards decided to join in raiding the Chinese countryside instead.”
“Emperor Wudi (140-87 BCE) learned that far off in the west a special breed of ‘blood-sweating’ horses carried men whose heavy armor made them proof against arrows... in 101 BCE, his emissaries returned from the Ferghana Valley (in today’s Uzbekistan) with a few such horses and the alfalfa on which they fed. But it turned out that feeding the big horses in Chinese landscapes was so expensive that China never maintained large forces of armored cavalry.” [J R McNeill & William H McNeill, The Human Web, p. 67-68]
“Greek armor was not cheap. ... Altogether the hoplite's ensemble might weigh from sixty to seventy pounds and cost 100 to 300 drachmas -- the equivalent of three months' wages for a laborer.” [Victor Davis Hanson, Ripples of Battle, p. 229]