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If you really need it, go for it. I have a barclay card and it never got above 20% utilization. They CLD me with a zero balance. So now it just sits in the naughty drawer. barclays is bi-polar
I would call in and see if they can increase your limit just for the hell of it, but then regardless I would go ahead and use it if you need the computer.
Barclays seems to love clean young files. They were one of my first cards when I was rebuilding (for a Macbook Pro purchase in 2013) and I maxed it out (also started at 2k). Then in 6 months they doubled my credit limit. Your Transunion score seems very healthy compared to mine (if yours in your sig is up to date). My TU score was in the lower 600's when I was approved for the $2k starting limit back then - with a collection account on my file at the time.
People say Barclays loves to CLD... but honestly if you are just starting with them I think you are fine. I *ALWAYS* have a 50-75% UTIL on my Barclay card due to the great promotional BT offers they seemingly always have offered to me. Never any CLD. In fact numerous CLI and they are always throwing out new offers for new cards all the time.
If you haven't purchased. I would try the PayPal Credit option, it only presents in checkout in full desktop mode on the payment page. It doesn't report month to month on CRAs, so there's a plus there. However if you're not going that route, check the pricing on the 2015 models on Apple website, not the refurb section. That way you can go through the education discount, which doesn't apply to certified refurbished items. If push comes to shove and your refurb is better hardware spec wise, then going new/custom new, then you also have the option on the education site in checkout, to apply for the Citizens One Education Loan, it's another hit but the bonus, if you have someone that can be a co-applicant, this is the only one that will let you use someone elses credit alongside yours. But like someone else pointed out, I've had the Barclay Apple Card a few years, the initial financing I maxed it and had to use a 2nd card to pay the remaining balance, since you can split payments in checkout once you have the permanent card in hand. I paid that off in less time than gave at 18 months. Then got another offer to finance and credit limit increases after tthe fact. Like you also mentioned utilization is short term memory, don't let the whole CLD from Barclay spook you, it's not relevant to everyone, but what I would suggest, keep utilization low on other cards if you can during that timefrarme, so you don't take a total dive in points.
Barclay might give you CLI with SP.
But if it will be HP why don't you apply for Citi Diamond or simplicity for 21 months 0% apr