An oldy, but a goldy:
Rollercoaster Tycoon 3 Platinum. It includes the expansion packs Soaked! and Wild!
Steam PC - Only £3.74
Rollercoaster Tycoon 3 Platinum combines the excitement of rollercoasters with the fun of a great strategy simulation. RCT3 Platinum combines the roller coaster theme park fun of the Roller Coaster Tycoon 3 with included expansion packs Soaked! and Wild! Now enjoy more options than ever.