It will take a lot more material than you'd think, and since it is your first time ever doing one, it'll take a lot longer than you think also getting every panel figured out and installed/trimmed. I would quote the interior separately, as it will be an entirely "different project", which will be very expensive compared to the amount of materials used, as it will be very tedious and labor intensive. I would roughly guess around $2000 for a basic "color change wrap", and around $3000 for something custom and wild looking. The interior will probably be around another $1000-1500 I would guess.
You might want to look into hydrodipping or plasticoating for this project.