First come, first serve:

    int64_t nSubsidy = 0 * COIN;
 
    if(pindexBest->nHeight <= 500)
    {
        nSubsidy = 1000 * COIN;
    }
        else if(pindexBest->nHeight <= 2500)
    {
        nSubsidy = 500 * COIN;
    }
     else if(pindexBest->nHeight <= 4500)
    {
        nSubsidy = 250 * COIN;
    }
     else if(pindexBest->nHeight <= 10000)
    {
        nSubsidy = 100 * COIN;
    }
     else if(pindexBest->nHeight <= 15000)
    {
        nSubsidy = 50 * COIN;
    }