The Gear Shop is a store accessible through Arena Combat Mode in Madness: Project Nexus (Classic). The shop sells both Weapons and Armor for the player to purchase. The weapons and armor available to you depend on your player's level. For example, the only guns available at the start of Arena Combat Mode (Level 1) are Walther PPKs, Beretta 92s, and Browning HPs. Absolutely no SMGs, Shotguns, or Rifles. Unfortunately, you will not have enough money to buy any of these.
At level 20, all weapons will be unlocked allowing you to purchase them if you have the money. The probability of seeing a scoped, lasered, or both scoped and lasered weapon is completely random, they do not correlate to your level nor how much money you have.
However, almost all armor is available to you from the start, but with a very small selection to choose from at a time. In most cases, even high level armor can be found at Level 1, but obviously cannot be purchased or even worn until a high enough Endurance stat is reached.
Below is a list of all weapons that are unlocked for purchase at each level as of V1.8.