Astrobrat needs yet more help!

Astrobrat needs yet more help!

I have encountered another trigger problem on my map Sim City. This time I know it has to do with triggers. You are supposed to be able to go into Mac's Garage, and there is an object called Buy Horse 100 Gold with a region on it named Horsemacsgaragered. You are supposed to be able to move on it, and if you have 100 gold or more, a Horse belonging to red will appear on another region called Macsgarage. Then it is supposed to take away 100 gold from your rescources. I have tried many ways to do this, yet I am still certain there is a way. Any help?

Event: a unit enters region macshorres

Condition: Owner of entering unit has 100 gold properties (Im not exactly sure how it goes)

Actions: create 1 horse at macshorseregion for owner of triggering unit.
Player -> remove 100 gold from owner of entering unit's gold.

My problem is in the Condition and part of the Action. Where are the triggers that check how much gold the player has, and the trigger that takes away gold?

I have found a way but i dont know how to make it easier
maybe it will beable but i have found another way:
First make a Variable named Gold_of_Player as a Integer
Than the trigger
Events:
A Unit enters (your region)
Conditions:
None
Actions:
Set Gold_of_Player to Player - Gold Proberty of Owner of Entering Unit
If/Then/Else Multiple Actions
If Conditions:
Gold_of_Player bigger as 100
Than Actions:
Set Gold_of_Player to Gold_of_Player - 100

Player - Set Gold Propertie of Owner of Entering Unit to Gold_of_Player

Create 1 Horse at (your position)
Else Actions:
Do nothing
If it works it will good i dont know it but i think it works.

There is no need to set the gold variable twice. To take gold away, you just do "Add property" and input a minus figure. That makes things easier.

I am really confused and I was imagining this as gonna be really simple when I started =(. Can someone please step-by-step the trigger?

Come on people, please help me.