There are many in-depth guides and forum arguments over what the best strategy for buying is. One such guide, written by the Professional Counter-Strike Team Dignitas can be found here. While there are many theories on what is best, it ultimately comes down to what you are good at using and how you want to play.

Mechanics

The mechanics for earning money to buy equipment at the beginning of a round, as explained in the above linked guide, are as follows:

"If the bomb explodes or is defused, the winning team receives 3500$. Of course, the planter or defuser also gets 300$. Once all enemies are eliminated, the victorious squad receives 3250$. To compensate for a lost round, the team that has lost a round will receive 1400$. If they continue losing consecutive rounds, they will receive 500 extra dollars on top of every compensation they get.

1 round lost: $1400

2 rounds lost IN A ROW: $1900

3 rounds lost IN A ROW: $2400

etc…"

Another important thing to consider is that, upon death, a player drops his/her most expensive weapon, their most recently equipped grenade, and if they have one, the bomb or a defuse kit. Once dropped, players from either team may pick them up from the ground with the exception that only terrorists can pick up the bomb.

Additionally, the player receives money for eliminating other players. The default value is $300, modified by the weapon used. For a knife kill, they player receives $1500, while for an awp kill, the reward is merely $100. One other item of import is that shotguns reward a hefty $900 while being generally inexpensive, thus making them a good option for cash strapped players.

Application

Applying these mechanics to the set of 30 rounds divided into 2 halves of 15, there are a few universal practices to understand.

To begin, for each first round of each half, all players are given $800 to begin. On the terrorist side you will be given the Glock, and on the counter-terrorist side, you will be given either the USP-S or the P2000. Each of these has their own unique tradeoffs.

Depending on which side you are on, the first round strategy is slightly different. If you begin as a terrorist, it is common practice to buy an alternative pistol to the Glock as it has very low damage (often taking upwards of 7 shots to eliminate an enemy), unless you are confident that you can get a guaranteed headshot when necessary. If you are counter-terrorist, your starting pistol is relatively effective, allowing you to buy armor if desired or grenades to prevent the common first round T (as in terrorist) rush. If faced with a T rush, attempt to slow them from entering while alerting your teammates and staying alive to help them retake the bomb site. For the sake of space I will refrain from talking about more advanced strategy in this section.

Past this first round, things become more unique to the situation at hand. However, upon a first round loss, your team has three options, two of which are viable. Your team can either save money the second and third round by not buying and attempting to pick off an opponent or two in hopes of obtaining their gun and saving it for next rounds, "surprise buy" in the second round, and, if this round too is a loss, saving until round 5, or you could force buy every round. Teams that force buy every round rarely end the game with more than 5 rounds won.

Another starter tip is to become familiar with one gun from each class, and use only that. Familiarize yourself with the following to quickly master the most commonly/easily used:

For a pistol, the P250 is surprisingly effective for its price. Mastering this will allow you to be effective even in rounds where you are pressed for cash. It also makes for a great backup when in combat and in need of a reload. It is much faster to pull out your pistol to get that last shot in than to reload your primary weapon.

For an SMG, the p90 is the most common choice to master. Unfortunately due to the price I would advise against having this be the first SMG to master. Instead I would recommend practicing the mp7. Hold down the trigger and aim down as you fire continuously.

For a rifle, I recommend learning the M4A1-S for counter-terrorists, and the Galil for terrorist. The most common terrorist gun to use is the AK due to its 1-tappable first shot that can instantly kill an enemy; however, it is wildly inaccurate and takes many hours of practice to master.

Some general questions to ask yourself to decide on what, if anything, to buy are as follows:

-Did anyone else buy anything?

-Does the gun I want to buy fill a role someone else is already fulfilling (i.e. are there already (at most) two snipers)?

-Does everyone on the team have enough money to buy?

-What position/role will I play this round?

-and many others.

NOTE: Due to the ineffectiveness of the starting pistols against armor, using them past the first few rounds is generally a bad idea. Even if you are not buying anything to save money (commonly referred to as a "save round") it may be a good idea to buy the P250, a surprisingly effective cheap pistol. It only costs $300, and can be effective provided you can get a few quick shots off before you get blown away by the people with big expensive guns.