The Flamer is the 5th and 1st of the medium weapons which comes with 200 ammo, 2 upgrades can be bought: damage increasement and movement speed.
The Flamer delivers damage, which can be increased with an upgrade, has a high firing rate, and 200 ammo.
It is not recommended to buy this weapon at all and should only be purchased if you're an up-close kind of player. Damage increasement should only be purchased in this case.