If you are looking to build a rental empire, then contact property managers directly. 

Here are some new Member TipsTip # 1: How to Use @Mentions on BiggerPocketsTip # 2: Setting up Keyword AlertsTip # 3: 25 Tips for Real Estate SuccessTip # 4: Check out the Start Here pageTip # 5: Check out BiggerPockets Ultimate Beginner's GuideTip # 6: Listen to BiggerPockets PodCastDon't know which one to listen first..listen to BiggerPockets Podcast 108: Building a 350 million Real Estate empire using the 10X rule with Grant CardoneTip #7: VotesTwo things you may find useful:1.

We have slowly grown our "empire" through pure rentals and other houses we have rented when we leave! 

what are the best sites to move a property under contract in the inland empire???

As has been said, you cannot build the empire states building on a 6inch slab.

I'm curious if there is any inland empire or san diego county agents that can give me more detailed cost list to the first year of being an agent.

Perhaps communities in west Inland Empire with the new 99 Ranch Market in Rancho Cucamonga, such as Claremont or Upland. 

But the idea that you will find 10% deals in CA simply by changing your search from SD/OC/LA to Inland Empire is wishful thinking.  

I was looking at the old posts on BP and came across this link http://www.biggerpockets.com/forums/86/topics/103036-inland-empire-real-estae-club.    

Launch that new product, take it to the next level, buy real estate, build an empire.