Zip has 301k searches maybe but why should that matter for the word zippaa?
The letter "S" has nearly 7,500,000 exacts for that matter but it does not make every domain that contains it valuable.
Had you registered "Zippa" then you may have had a fairly valuable domain, with its ease of spelling, the double A is just confusing and makes it fail both the phone and radio test where you have to explain it to people. You should be able to just say it once and people will "get it"
Hmmm thanks for your suggestion. I sold zipaa.com in mid xxx$. but i donot own zippa. I also think that zippaa also has good potential. Any more Appraises ??