Simple Math or "Yes, please pay me to get a new iPhone."

I've had an iPhone 4 since they came out.  This phone has been resilient even through all the flying leaps I put it though over the last few years.  But when it came to being time to upgrade, I did some quick research.  I found a company that buys old cell phones for a fair price (in my opinion for this transaction).  Assuming the USPS doesn't destroy the phone on the way to Gazelle, they will give me $150 for my old phone.  Through AT&T, I was able to find the same model for $0.99.  Of course, there's a $36 activation fee, but ultimately getting a new phone is going to result in a $113 profit for me.  I'm OK with this!  I'm also OK with sticking with the old model of iPhone for my business because I don't spend a lot of time on the phone and it allows me to use Square for purchases made by folks using credit cards.  I quite enjoy the simplicity and speed of Square.  I know other credit card processing for smart phones have come out since Square, but I haven't had any issues with Square to date so I haven't bothered to look into the other services.  Technology has really revolutionized the way I do business.  Before smart phones and Square, there was no credit card processing at craft shows.  It was just too cost prohibitive.  But now, depending on the show, over half of my sales could be credit card.  That's a huge increase in revenue!