I have a selected few that I shop frequently on without having much issues with payment. Most of the time, I shop with COD mode of payment unless I have other reasons not to. Apps include Snapdeal, Amazon and flipkart.
I don't usually give my financial information to any site or app, unless it is well known and trustworthy. If I am not sure of the company, then I use the cash on delivery option. Only when I am sure of the reliability of the app do I give my details.
There are three payment options available for me: paypal, payza and bitcoins. paypal is more common compared to payza and bitcoins. Paypal and payza have dispute options, you can get 100 percent refund on your transaction. I use paypal app when I make online payment to the items I have purchased.