I've been playing dCity quite a bit lately. I'm quite liking it and very excited for the coming update!
I've already got some pretty rare cards including an airport (3% drop chance) and a Hive sign! (1%)

I'm getting very close to the top 200 cities where I'll be able to start getting rewards daily! If my factories sell (btw im selling some factories) I'll be able to buy the houses and population I need to reach top 200.

My general strategy at the moment is get up to 800 SIM income a day and reinvest by buying a new card every day. After that who knows, plan will probably change when the update comes out in a couple of days.

I was going to say something about how getting the daily rewards would never cover my investment so far but the I remembered I still have my cards which themselves hold value so it's a sure win to get to the daily rewards threshold, which is the top 200 cities.

As for getting started, I think buying SIM is the best way to start as there are some cards that are cheaper than buying a random card from dCity itself, It's 800 SIM for a random card where as at this time basic homes (the most common drop) are on the market for below 300 SIM!

The economy in this game looks really healthy right now. The developers have done a good job so far!