Whatever they buy. Knives aren't an issue item, and soldiers buy them on their own.
bowie knife
Most of the models are red, because that is the Swiss colour of the Swiss Flag.Not all models are red, the model used by the Swiss army is brown, and other models come in assorted colours.
Stainless steel and plastic.
The pricing of a browning model 21 knife can be worst a lot of very little. It all depends on the shape the knife is in.
Army Rangers
There was a trench knife issued to US Army troops that was a knife that had a "Brass Knuckles" handle. Brass Knuckles is a brass "ring" that you slip over your hand, each finger going into a loop. This is used for hand-to-hand fighting. The knife had this same construction as part of the handle/grip. I'm not sure if this was an official Army issue. The Army preferred the soldier carry a bayonet that would fit onto the rifle. This brass knuckle trench knife couldnot do this.
that appears to be a benchmade model 147sbt, the nimravus cub.
The pay for Army Rangers is the same as any normal soldier because the pay is based on rank. Base pay is based on rank and pay grade. That being said, there are additional factors that would need to be considered to arrive at any individual Army Ranger's gross pay.
The US Army issues several types of knives, and in addition to that soldiers can carry their own knife or knives. Most popular and widespread models are Buck M9 field knife, which also doubles as a bayonet, Kabar and Ontario military knives. During Vietnam era SOG bowie was issued as a standard knife.
The one I used to carry, the Swiss "officier" model, by Victorinox, has 9 tools: 3 and 11/2 blades, screwdriver, corkscrew, can opener, saw, short punch, twezzers and tooth pick.
i don't think that they really used a specific kind of knife.
In the majority of episodes MacGyver uses Victorinox Swiss Army Knives. The opening title sequences does show a clip where he was using a Wenger knife, but most of the time it's victorinox. According to the MacGyver Online web site which has a list of all the knives used in each episode the most commonly used knife was the Victorinox Spartan.