1. If you use Applet based trading platform like Reliance's instatrade, or Software based like odindiet or powertrade etc.. they show Total Buy (bid) QTY and Total Sell (ask) Qty. That means you need realtime data feeds.
Alternatively, go to
http://www.nseindia.com, get quote of a scrip, say RPL, you can see "Total Buy Qty", "Total Sell Qty " there but it is a bit delayed.
2. Scalping is taking small profits many times.. say you buy rpl at 170 and sell it at 170.5 or 171 (taking a profit of 0.5 to 1 tick). if you do this 10 times, you'll get 5 tick profit 100 shares*(10times*0.5 profit) = 500
so, you are having 17200, you can do 100 shares of RPL. if say RPL falls to 166.. then you may convert it to delivery.. and wait till it comes back to 170+deliverybrokerage+taxes = 172, which is usually the next day.
this way your bad trades will only result in "Suspension" of your price.. but only do scalping with the money you can throw away.
scalping is overwork and tiring.. so better avoid it..