which is buy or sell price

I am using tickers to fetch current price of stock at which i can sell or buy, there are many values in output i need which is that value which i can consider to buy or sell a stock ?
which among following is price at which i can buy or sell stocks
double lastTradedPrice = ticks.get(i).getLastTradedPrice();
double close=ticks.get(i).getClosePrice();
what is difference between
getTickTimestamp and getLastTradedTime
i have refered example mentioned in github but i dont see either
function tickerUsage or main gets into infinite loop as we need to keep fetching realtime value , do i need to put an infinite loop explicitly as program might exit after a while if not put.
Example:

 try {
            tickerUsage(kiteConnect,tokens);
        } catch (IOException ex) {
            Logger.getLogger(TickerPrice.class.getName()).log(Level.SEVERE, null, ex);
        }
     while (true)
        {
            try {
                Thread.sleep(100);
            } catch (InterruptedException ex) {
                Logger.getLogger(TickerPrice.class.getName()).log(Level.SEVERE, null, ex);
            }
        }         

how many tokens i can pass to so that i can fetch in single tick by tick , is it possible to fetch tick by tick info for 200 to 500 stocks , if so please point me to some example.