My car doesn't have keyless entry and I was wondering if this can be added easily. Is there an Audi factory add-on that can enable this or is there an aftermarket solution that's widely used and accepted?

I bought my vehicle used without the Remote.
(Look for the IR sensors on the B-Pillar)

The remote is $168 bucks for the remote with integrated key from the dealership.

I'm waiting for the winter when i'll need it before spending the bucks.

Sam.

My seats are preheated durring the winter, windows defogged, ready to go.

Durring the summer, the air inside is nice and cold.

Bunch of friends pitched in to get it as a gift, so not sure on price.. but it has alot longer range than my old keyless entry did.

If you want more info on brand, etc, let me know!