Having the cash is great ... keeping or growing it is better. Here's my experience. 

If you want a car, buy for the long run ... to keep your money.

I bought a one year old Honda Civic Coupe with 75 kms. at the dealer in 2009. I paid cash and I haggled ... remember YOU have the advantage and they will try every trick to get their price. Just show you don't care and are prepared to walk. They started at $23.500 and I got it for $20,000 ... had everything I wanted too and never a problem driving from Alaska to Key West over all kinds of roads.

Now that you have an economy car at a great price and high resale value proceed to the growth bit. At your age start buying dividend growth stocks. Over the past 30+ years that's what I did  Buy all of the following- CN Rail, TD Bank, Emera, Fortis, Canadian Utilities, Enbridge, Trans Canada, Telus, Power Corp, BCE, Brookfield Infrastructure, Canadian REIT. Reinvest the dividends, sit back and grow rich. It's slow to begin with but hang in there