You can look up used vehicle values on nada.com and edmonds.com. Or you could search completed listings for similar vehicles that have sold on ebay.
4% of 73000 = 4% * 73000 = 0.04 * 73000 = 2920
73000
12% of 73000 = 8760
73000
42000
22,630.
4.08%
73000
73000+
36500000
73000
73,000