2000 Camry often tart due to not in park properly

2000 camry xle v6 105,000miles

Poblem started about 6 mos. Ago. Have o take out of park and put in neutral or put back into park a few times to get it to start. (Won't turn over or anything) What ears out when this happens? It's an automatic with a console style shift. I'ts happening more often, so I'm sure what ever switch or contact it involves is about worn out. Is the problem located in the console area or under the hood?
Name of part needed, esitmate of cost, level of difficulty to repair would be appreciated.

Thx, Jeff