Javelins are portable anti-tank missile. Stingers are portable anti-aircraft missiles.
A Javelin missile costs about $80,000 (Wikipedia) and weighs 49 pounds. It can be fired by one person. It has infrared radiation tracking to locate its target, which can be a tank or low flying aircraft such as helicopters. Per Wikipedia: “The missile system is most often carried by a two-person team consisting of a gunner and an ammunition bearer, although it can be fired with just one person if necessary. While the gunner aims and fires the missile, the ammo bearer scans for prospective targets, watches for threats, such as enemy vehicles and troops and ensures that personnel and obstacles are clear of the missile’s backblast.” Also, Wikipedia notes that the exhaust from firing the missile contains lead. Gunners are instructed to hold their breath during firing. The Javelin is a “fire and forget” weapon as after firing, the team can quickly relocate to avoid enemy fire. See links:
It is unclear how many Javelin missiles and launchers Ukraine currently has as they are actively using up their supply and more missiles are likely being sent from the neighboring countries. Wikipedia states Ukraine has 377 launchers and 1200 missiles. The actual number is likely higher than this as there has been air shipments from Poland.
Stingers are portable surface to air missiles, and similar to Javelins, they can be fired by one person, but usually a team of two is used. A stinger weighs 33.5 pounds, and has IR and UV detectors to track the target. Apparently, adding UV detection increases the reliability of target seeking electronics. The missile is also capable of being deployed from a Humvee Stinger rack, and can be used by airborne troops. A helicopter launched version exists called Air-to-Air Stinger (ATAS).
Stingers are also “fire and forget” missiles giving the team an opportunity to relocate after launch.
As shown above, a small ejection motor in located behind the missile. The motor pushes the missile out a safe distance from the operator before engaging the main two-stage solid-fuel sustainer, keeping the gunner safe from the missile thrust. (Wikipedia) The cost of stinger missile is $119,000.
Wikipedia reports that the US has sent 2,000 stingers to Ukraine. It is always difficult to know how many Ukraine has available at any moment, as they are being used and more are being slipped into Ukraine.
More technical details can be found in the links.
There are many informative websites on these missiles, and their use in the Ukrainian war.