If you don't know much about online trading, I wouldn't experiment w/ my hard earned money. 20k is a lot of money. You can try trading on Ebay or Amazon. Look for deals on CL. Buy at a cheaper rate on sites like overstock or even in stores like Marshall's and sell your purchases, making some profit. Buying gold (1 oz.) when the market plummets and selling it when the market's up is another effective idea that I've tried and succeeded in myself. 

चुदियो का दुकान is another excellent idea but if you already have a job, you're better off staying away from this sort of venture.