For the last 3 months I hadn't bothered unlocking the 1000 Ticket and the Level 12 Ticket, even though it was in the Car Delivery section the whole time.
I only have about a million credits, and the most expensive car I bought with my own money thus far is a 458 Italia. Reading some of the horror stories in this thread, I set my expectations low. I'd have been perfectly fine with something like a Mazda RX-7, honestly.
I'm pretty pleased with the results:
Level 12 Ticket: Jay Leno Tank Car - 3,997,280 Cr.
1000 Ticket: Lamborghini Miura P400 - 15,000,000 Cr.
Ballin'!