So I need an I-Pod adapter for my car. I used to have this cassette thing, but I got a new car and don't have a cassette player in my car anymore. What can I use? Please find me something from a store like Fry's Electronics.

Here's exactly what you need: An FM transmitter. This is a little battery-operated gadget that plugs into your IPod, or any other MP3 player for that matter, and transmits your music through a station on your FM dial.
You can buy a transmitter specifically made for your IPod, but if you want to save a little bit of money, you can buy a less expensive one just about anywhere. The one we use in our car cost less than $20. Transmitters can be purchased just about anywhere that has electronics.
The two FM transmitters I've shown below are just two from a whole page on the Fry's Electronics website. I've also given you the website link for all the transmitters they offer. They're offered at anywhere from $5 up to $100, but you really don't have to spend $100 to get one that will let you enjoy your IPod in your new car.
However, the one I would recommend is the Belkin TuneBase car adapter. This handy gadget, which only costs $10 on Amazon, plays your tunes through your car stereo and powers your iPod at the same time.
This unit lets youuse the iPod display for quick and easy tuning, and features four,single-touch programmable preset buttons that let you find the clearest frequencies, and toggle among them for optimal performance. TheTuneBase's holder provides a secure and stable connection to your iPod with a custom-designed cradle.
Belkin is a great brand and I think you'll really find that this gadget will allow you to completely enjoy your IPod.