01-02-2017, 05:43 PM
It's a cheap no brainer to replace the battery. In fact I'd do that even if I was going to buy a new phone so that I'd have a spare phone and/or music player for the home. Next, I'd decide exactly which phone I wanted and then buy it used. I certainly wouldn't buy a 6 Plus if I really wanted a smaller phone.
To figure out the best deal, add up the cost of the phone downpayment + installment charges + service for each option over the 2 year (or whatever) period over which you'd be buying a phone on one of the installment plans. It doesn't make sense to compare monthly costs if some plans include installment payments and/or down payments and some don't. Also, you don't mention the option of keeping the iPhone 4 and going to a cheaper data plan. That's probably your cheapest bet.
To figure out the best deal, add up the cost of the phone downpayment + installment charges + service for each option over the 2 year (or whatever) period over which you'd be buying a phone on one of the installment plans. It doesn't make sense to compare monthly costs if some plans include installment payments and/or down payments and some don't. Also, you don't mention the option of keeping the iPhone 4 and going to a cheaper data plan. That's probably your cheapest bet.