What kind of gold you looking for? Gold as investment or jewelry?
for jewelry you can go to Gold souk, you can take Karwa taxi if you dont know where is the souk. They will offer you two kind of transactions either you purchased by per gram or by fixed price. I prefer the per gram thing so you know how much per gram per carat gold. Last time I buy 18c gold which is 2 months ago was 130 riyals per gram thats including the making charges. for 22c is 135 riyals per gram.
and you can also purchased a jewelry gold in all Damas shop, and for our convinient they have a stand inside Carrefour.