Advice on getting first iPhone

I'm a long-time Mac user. I have a MBP and I use it mainly for Logic Pro. I'm thinking of getting an iPhone just because I need a cell phone and I assume there must be some benefits to having an iPhone when you have a Mac.

I found a used, unlocked iPhone 7 with 32GB for $450, an iPhone 6 64GB for $333, and I'm sure there are other options out there on Amazon. I don't know what the advantages of the 7 are, but double the GB and a lower price make me lean towards the 6.

The phone I'm coming from is really bottom of the line so anything I get will be a big upgrade.

Can anyone tell me whether I should invest in a newer iPhone, invest in extra GB, and what will be the benefits to having one in the first place?

The 6 is fine and you get more RAM which is really desirable.

You will also get a built-in headphone jack.

On MacRumos I'm getting the opposite advice. I mean, they're saying don't settle for anything less than a 7 or a 6s because the 6 has only 1GB of RAM. The headphone jack does make a difference though. I can't imagine how annoying it'll be to constantly drop the "air buds" and eventually lose them cause they're not connected to anything.

It's worth mentioning that I posted here because my perspective is that of a Mac user with a focus on Logic Pro. I understand the iPhone doesn't have any remote benefits like the iPad does, but I mainly just want a good phone that I can synch with my Mac.

I was looking at this one because it has 128GB: https://www.amazon.com/dp/B00YD54FA4/ref=psdc_2407749011_t1_B00YD54DV0?th=1

But like I said, there's a guy in the area selling an iPhone 7 with 32GB for $450. My current phone has only 3GB of space and even after adding a 16GB SD it keeps running out of space but only because half the apps can't be transferred to the SD.

This is the best 6 I've found on Amazon so far: https://www.amazon.com/dp/B00YD54FA4/ref=psdc_2407749011_t1_B00YD54DV0?th=1

While there's a guy in the area where I am selling a 7 with 32GB for $450. I'm a little conflicted... I think I'm leaning toward the 6. Cheaper, more GB, headphone jack. On MacRumours, they also mentioned that the 6 wouldn't guarantee upgradeable OS for very long.

It all depends on your needs.

The 7 is much faster, more RAM, better camera, 3D touch... yada yada yada.

I personally find it being half baked. The next revision will probably be more of an innovation.

Test the latest 7 out against a 6s or 6 in the store and see for yourself.

Cheap-ass ...  ... that I am, I found an IPhone 5 on Amazon for a couple hundred bucks. It was a unit that was guaranteed to have never, ever been used by anybody, and it was likewise guaranteed to be eligible for AppleCare® warranty support. (Which I subsequently found [on-line ...] to be true, based on the serial number, and which I subsequently paid for.)

I resisted the "momentary lapse of reason" impulse to buy the thing at Wal-Mart ... and saved $250 ... for the same thing.  (Welcome to Apple Marketing!)

This was an easy variation of the exact same strategy that I have shamelessly used in buying almost all of my Apple equipment ... uhh, since the (bah! never mind!) I buy "last year's model."  (Or, in this case, a couple years.)  Somehow, they never sold it, and now, they're anxious to turn it into money.  (Or, they used it last year as demonstrators in their stores, then fully factory-overhauled it.)  Apple(!) continues to offer you the very same warranty bargain that they would have offered if this phone was still "the 'latest' device that you all should be dutifully salivating for."

And, lo and behold, it's still "a fantastic phone."

I simply don't subscribe to the notion that "now that model N has been introduced, each and every model N-x now sux."  Because it doesn't.  And, you can get the thing for many(!) hundreds of dollars less ... with an Apple® extended warranty.

(Obviously, you can't go too far back, because hardware changes do occur and the time will come when "iOS will pass you by."  But the "end-of-life period" for any such piece of electronics is actually quite a long time ... and fully disclosed by Apple, as the Federal Trade Commission requires.)