I had handmedown flips and then handmedown androids. I bought an iphone 5s. I'm not knocking Apple but I kinda miss the androids. There are some free android apps I'd find more useful than the paid iphone apps. I'll eep the 5s til I need a new phone and probably go back to android. Grouping my contacts was easier with android. So was dealing with email.
As for paying with plastic, I believe youre pretty much covered for any monetary losses by the card company. Debit cards may be a little less safe because that's your money. Having said all that I've been buying and selling online since 200 and never had any problems. Knock on wood.
Oh yeah and for android users, check your privacy settings close. You might be surprised at what you find. If you haven't unchecked tracking then google knows everywhere you have been and when and for how long.
Same for iphone but not as bad since they aren't so twisted up with google.