As the U.S. sells more modern weapons systems, a lot of used equipment, with a lot of miles left on the odometer, come on the second hand market. Earlier this month, for example, 24 UH-1H helicopters came on the market, at the bargain price of $225,000 each. But a lot of equipment is new manufacture, usually Russian. The same dealer (Ballistica Maximus Corp., St. Petersburg, Florida), offers newly manufactured Russian TM-62 anti-tank mines. These, and all other items that go "bang", require proper import and export documents. These can be forged (that's a major industry in itself) and arms dealers generally scrutinize the paperwork carefully. Get caught selling via forged documents, even if it wasn't your fault, and you can lose your own weapons deal permits.
With the right paperwork, you can also get refurbished T-80 tanks, complete with a three year warranty. Price negotiable, depending on quantity and urgency for the owner to make the sale. New BMP-3s, without weapons, are available for $199,500 each. You can get a sense of what the current market rate price for some common weapons is from such dealers. New M-16A2 assault rifles cost $869 (an M-203 40mm grenade launcher as an add on costs $1250). AKM-S assault rifles are going for $265 each. Light machine-gun are a lot more expensive, a new M-60E3 machine-gun costs $10,615. A new .50 caliber Barrett sniper rifle costs $7,920. A Russian RPO flame thrower costs $3,621.
Need something larger. How about a M-10A1 105mm towed howitzer? New, for $327,319. Need special ammo, the stuff you can't buy at Wal-Mart? This is also available. How about 81mm mortar shells? You get them for $63 each, minimum order 1,000 rounds (proper paperwork required.) Fragmentation grenades are available for $20 each, and individual rounds of .50 caliber ammo can be had for a buck (minimum order, half a million rounds.) Is all this is making you nervous, you may want some protection. Get a Kevlar helmet for $155. Maybe calling for help will make you feel better, Get a military two way radio, a PRC-77, for $2,734 (minimum order six). War is hell, and it ain't cheap either. All prices subject to change depending on supply and demand.