Buying online is it ok?

I find that you get more choices and better prices when you buy online, so I would say it is a good thing :)

However you need to be careful from where you are buying. I usually stick to sites which are well known (ebay/amazon or other popular ecommerce stores) and check that I can pay by Paypal because I know I would be refunded if the seller doesn't send me my package.

Why are you stressed?