Oracle confirmed that Apex support will be extended for 5 years from the date of product release. Please read the document,

“Oracle Application Express has a large and active installed base, with over 250,000 developers creating thousands of applications.  Oracle recognizes the considerable investment in Oracle Application Express and remains committed to the long-term support of this product.”

http://www.oracle.com/technetwork/developer-tools/apex/application-express/oracle-application-express-sod-1596338.pdf

My suggestion is use Oracle XE with Apex to start with.