Here is the key binds I use for the buy menu.
bind "F3" "buy primammo; buy secammo; buy flashbang; buy flashbang; buy hegrenade; buy smokegrenade; buy vesthelm; buy deagle; buy ak47/m4a1; buy defuse.
That is mine. However, F3 for me is the same, but I use an ak47; F4 is same, but with an m4a1; and finally, F5 is the same, but with an AWP (only use it on AWP servers).
Hope that helps. And remember that you can choose any weapon you want for your main weapon. You don't have to use a m4a1 or an ak47 if you don't want. Just pick a different weapon.
Pistols:
buy glock (9x19mm Sidearm)
buy usp (KM .45 Tactical)
buy p228 (228 Compact)
buy deagle (Night Hawk .50C)
buy elite (.40 Dual Elites) buy fiveseven (ES Five-Seven)
Shotguns:
buy m3 (Leone 12 Gauge Super)
buy xm1014 (Leone YG1265 Auto Shotgun)
SMG's:
buy mac10 (Ingram MAC-10)
buy tmp (Schmidt Machine Pistol)
buy mp5navy (KM Sub-Machine Gun)
buy ump45 (KM UMP45)
buy p90 (ES C90)
Rifles:
buy galil (IDF Defender)
buy ak47 (CV-47)
buy sg550 (Krieg 550 Commando)
buy famas (Clarion 5.56)
buy m4a1 (Maverick M4A1 Carbine)
buy aug (Bullpup)
buy scout (Schmidt Scout)
buy sg552 (Krieg 552)
buy awp (Magnum Sniper Rifle)
buy g3sg1 (D3/AU1)
Machine Guns:
buy m249 (M249)
Equipment:
buy primammo (Primary Ammo)
buy secammo (Secondary Ammo)
buy vest (Kevlar)
buy vesthelm (Kevlar+Helmet)
buy flashbang (Flashbang)
buy hegrenade (HE Grenade)
buy smokegrenade (Smoke Grenade)
buy nvgs (Nightvision)
buy defuser (Defusal Kit)
Copy this list and keep it with you for future buying binds
Cheers mate!