What is the best way to farm coins?

Infinity Time usually gives me 25k Coins, and a payout is similar to the Wave you reach or number of shards collected. This method isn't really ideal because you'll eventually run out of stars, but is still viable. Probably works out about 50k per hour, a run to 25k usually takes me just over 30 mins. No exp gained.

Suburbination

Difficulty: CRAAZY

Team Setup: Empty

Quickly capture all the points and just sit there until the game ends. Someone said you can make 100k per hour this way but I timed it and got half of that. This works out to be about 40k per hour if you take into account loading times. Minimal exp gained.

Gardens and Graveyards

Difficulty: CRAAAZY/Hard/Normal/Easy

Team Setup: Sunflowers vs Scientists

Try getting the Sunflowers to group up in the objective by killing a few of them in there, and kill them with Electrican/Electro Brainz, or other classes for slightly less payout. Payout works at around 50k per hour, maybe more. High exp gained.

Not sure how much per hour this gives but it's easy money and it's easy exp, it's a bit repetitive but anyone can do it.

If you prefer Team Vanquish against AI make sure you play Vanquish confirmed, as the orbs give extra exp and well better money as well I think.

-----

Or play online, any game mode. I wouldn't call this farming for coins as the payout will depend on class compositions and what you do in the game.

Edit: Oops, just realised I repeated @xxSe4l-MLG420xx said too, ah well.