I sometimes play SC4 without any mods at all, just to prove that I
can run a city successfully without going broke--usually I gotta have my mods though. For me, it's more fun when I don't have to think about money--transportation and pollution are headaches enough--so I have a mod that allows me to start with some insanely high amount of money. The mod also puts a big multiplier on the incoming taxes, and I wish it didn't do that, but I don't know how to change it. I wind up setting all the tax amounts to 1% just so that it's not always operating in the black. (I got the mod at Simtropolis--can probably find a link for it if anyone who is tired of running out of money quickly wants it. My version is for SC4 with RH, but I think there is one there for SC4 only, as well.
Actually now that I think about it, even when I don't have in the simoleon mod, I still have to have the network add-on mod and the fix to prevent the opera house from trashing the entire education system, so I guess I can't play with "no mods at all." Hmm.
For me SC3 was the easiest of them all. For SC2000 I had to use the funds cheat most of the time, but with SC3 it was just a matter of accepting a couple of the deal offers early on and demolishing them once the city could support itself. I still liked some of the cheats though, particularly the one that caused ALL industries to be high tech. And the "call cousin vinny" thing--I think that's SC3 and not SC2.