One of the tricks this game uses is special buildings to get you hooked on instant returns, but then they can't be upgraded and you will hate them and remove them later in the game.   A  fancy house (blue) gives 20% more workers for 250 gold.   To get that house to level 8 will cost you 31,675 gold during multiple 50% off sales.   Unless you buy gold, you will never get past level 3.  The same easy to start, hard to upgrade trick applies to adventure buildings, fertile fields, free range orchards and stables, and gnome houses.   My general rule is pretend paw prints do not exist and if you build, focus on 1 of each building type – adventure coins, purple tickets and keys.   If you choose not support the developers by purchasing a package, avoid fancy houses and fertile fields.