Acquisitive Stepdaughter(s)

Bit of backstory: A couple years ago I married a man with two daughters, who are now 14 and 11. Their mother is a basket case who has nothing but supervised visitation that she rarely takes advantage of. Before she finally moved on with her life she was a black hole of crises and an expert at spending money.The girls are no longer on good terms with her and the younger has started calling me Mom. I feel a basic level of connection with them because my sister and I are almost exactly the same age gap and also grew up with some selfish-ass, crazy parents. Dad and I work hard to give them a stable environment and anything they need. Dad however has a history of assuaging his own guilt by spending money.It's gotten to the point where half the conversations I have with the 11 year old are her asking me for something. Can I have your lamp? Can I have some [insert inappropriate food item here]? Will you take me to the store? Every day she has some new thing she just has to have, and gets angry and screechy when I give her an answer she doesn't like.Which lately is often because it feels to me like she's looking for validation through consumption. It feels greedy and unhealthy. It's not that I don't spend time with her, I tuck her in every night, take her to school every morning and just today my 5 months preggo self took her on a 2 mile hike. The hike went well and I felt good about giving her an experience rather than stuff, that's much more my speed.Then she spent all evening asking for a new tablet because she broke her old one. When I was a kid the greatest things I ever got was a TV in my room. I am fed up and am seemingly the only one who sees it this way. Hubby is getting there but I feel alone here and wonder if I am overreacting.What do all you parents think? via /r/Parenting http://ift.tt/2opcK7Z