Now another question appears "How long do I have to spend on the game to have profits?" Not much, but you have to play systematically. Here’s the deal: you put 1 worker to work on a 1st level building and this takes 3h. After these 3h, you just log in and click again to work on building.
1st level building with one worker
The same building with 8 workers and as you can see below there is an option to finish this proccess in no time but for 0.157 gold which is very expensive.
As you already know, there are two ways to build them faster: add more workers to one building or pay gold for instant building. Let’s assume you only have 10 available workers and you put them all to work on one building and, in the end, build 10 building using the same workers: the time needed would be equal to 1 worker per building having 10 buildings to build. This gives a chance to everybody, so even if you don't really have time you can play as well as a person that has it, all you have to do is enter every few hours for 5-20 min (depends on how big your city is). For example I have to enter for around 10min on computer or 20min on tablet between 3h to 9h depends on how I put buildings. Second option is paying with gold, the building will be done instantly but it's too expensive and nobody does that, not even I. Spending more time will increase your profits but not much and you have to know how to spend this time – and this I will explain to you, just as everything else, once you decide to start your adventure with GoldenTowns.