OP, she's testing out your level of interest. Let your actions speak for you. Be yourself.
You noted an action of hers, buying your mother a bracelet. How do you feel about that? This is what I'm talking about.
If she doesn't have a lot of relationship experience, IMO it would be helpful to communicate about pacing, beyond what normally is shared through actions. This is really important to keep a couple emotionally in sync as the relationship grows.
Your example about the cell phone is a great one. IMO, you're not yet at that stage where you would have a lady on your cell phone account, regardless of you working in the biz. It's a boundary issue. This of course is personal, and I tend to take relationships more slowly, not because of lack of interest, but because of "too much, too fast" type of actions. For example, at the extreme, my wife and I did not live together until after we were married, but we spent many nights and weekends at each others homes during our dating and engagement period. You'll need to decide what sort of boundaries you want and communicate that to her. In the case of your example, I might have said "That sounds great, but I think this phone will come down in price and I might be able to get you a better deal on both the phone and the plan after I've been here a few months. Let's look some more." That acknowledges her interest and that you're looking out for her but sets a boundary that every advantage that comes your way doesn't automatically get assigned to her. Such is a privilege that is earned.
No red flags here (I don't see any incitement to or issues with jealousy myself). Have fun!
