[ConnorMcLeod]

Optimized a bit cause you shouln't get tha cvar pointer twice in the same function.
Also added a taskID, not needed at the moment but you need to do another task it will.

#include <amxmodx>
#include <amxmisc>
#include <cstrike>
#include <fun>

#define PLUGIN "Round Survival Money"
#define VERSION "1.0"
#define AUTHOR "X-Script"

#define TASKID 978645

new roundsurvival, roundreward

public plugin_init() {
    register_plugin(PLUGIN, VERSION, AUTHOR)
    
    register_logevent("round_end", 2, "0=World triggered", "1=Round_End")
    register_logevent("new_round", 2, "0=World triggered", "1=Round_Start")
    
    roundsurvival = register_cvar("amx_survivemode", "1")
    roundreward = register_cvar("amx_survivecash", "3000")
}

public new_round()
{
    if (!get_pcvar_num(roundsurvival))
        return PLUGIN_HANDLED
    
    client_print(0, print_chat, "[AMXX] ROUND STARTED: Survive this round and win an additional $%i!", get_pcvar_num(roundreward))
    return PLUGIN_HANDLED
}

public round_end()
{
    if (!get_pcvar_num(roundsurvival))
        return PLUGIN_HANDLED
    
    new players[32], totalplayers, player
    get_players(players, totalplayers)
    
    for (new i = 0; i < totalplayers; i++) {
        player = players[i]

        if (is_user_alive(player)) {
            
            new money_to_give = get_pcvar_num(roundreward)
            cs_set_user_money(player, cs_get_user_money(player) + money_to_give)
            
            client_print(player, print_chat, "[AMXX] ROUND ENDED: You survived and have been awarded $%i!", money_to_give)
            
            set_user_rendering(player,  kRenderFxGlowShell, 255, 255, 255, kRenderNormal, 0)
            set_task(8.0, "glow_off", player+TASKID)
        }
        else 
            client_print(player, print_chat, "[AMXX] ROUND ENDED: You did not survive this round. No award for you. Better luck next time!")
    }    
    
    return PLUGIN_HANDLED
}

public glow_off(id)
{
    id -= TASKID
    set_user_rendering(id)
}