1) What is the minimum cost to become partner (ISV/OEM)?
Becoming an ISV partner costs nothing. The tools (all you can eat developer orgs, partner support, technical library, tutorial material, training courses and webinars) are free. Listing an app costs money.
To list on the AppExchange and license your application to Salesforce customers will cost you the initial security review fee of $2700 (then renewed annually for $150) and 15% of your app's revenue. This is known as the Standardized partner program.
2) Is my production org license required even I pay 15% revenue to Salesforce per user per app?
Once you have paid the Security Review fee, Salesforce will give you two Enterprise Edition licenses gratis which you can use to administer your Licenses, Subscriptions, Orders etc. But yes, additional licenses must be purchased at full cost ($135 per person per month).
3) I plan to deliver my application in Asia so is there any variation on the cost for revenue?
No.
4) I have to pay security review fee ($2700) while joining time (before releasing my App)?
No. For free you can become a partner, seek support, develop and test your application. Only when you want to list your application on the AppExchange will you be required to pay the security review fee.
5) What is the criteria to become SF partner? I heard that I must have certification to join?
Registration itself carries no requirements. As opposed to the ISV partner program, the Consulting partner program ("Cloud Alliance") is more about generating sales and delivering implementations. But if you want to participate in a tier program (silver / gold / platinum) there are competency, certification, revenue and customer satisfaction requirements.
Best Answer
Salesforce allows you to build an application, called an OEM application, where your subscribers do not pay salesforce.com directly for licenses, but instead pay the OEM partner directly. In turn, the OEM partner pays a percentage of its license revenue to salesforce.com. Typically, salesforce.com loses a few bucks per license, but is still gaining revenue through volume licenses, and they don't have to deal with subscription costs, sales, marketing, etc. The standard OEM agreement prohibits Leads, Opportunities, Cases, etc (the "CRM" part of Salesforce), but allows custom objects, API access, and so on. The OEM wins because they no longer have to deal with hardware and platform software or system upgrades and maintenance, and can focus on building their purpose-built application. Here's more information about the OEM license types.