About DSLR camera kits?

Okay so I'm really young, really really young. Buying a professional camera has been a dream since I was a little kid, I always liked taking pictures. My Best friend told me a few days ago that she might buy one. I thought about it for the past few days and I did a tad bit of research and I found a man selling a Nikon D40 for a thousand and a half where I live and I can't find a way of telling my mother about this. My mother was never the understanding type. She would probably say no before knowing what I actually want. I just want her to pay about 800 only, which isn't too much considering where I live and this is going to be my next birthday gift and I don't have any way of making money because I'm not old enough to work, I got the money I have from my family in holidays, they give me money for my birthday and I saved the money since I was little. The real question is, how can I tell her about this and are there better and cheaper cameras out there than the Nikon D40? Thank you.

Added (1). A thousand and a half is about $400. And I just want my mother to pay me about $200.

A D40 for "a thousand and a half"? That's about three-four times what it's worth, kid. $800 is way too much. A D40 with a kit lens (nice outfit… I had one) shouldn't be more than $400.It's been discontinued for a while. Check with Adorama… They run some good deals.

If you're really really young, you still must be a kid!

A decent Nikon D40 from where I'm don't go beyond $400 secondhand. To conclude the purchase, you must bring an adult with you so the seller won't be tempted to fool you. Bring an adult you trust and who knows about dSLR's so you can have it tested thoroughly before handing over your precious cash.