[General] Valuable?

[jenbug]

I am not at all familiar with Pokemon cards but recently bought a storage unit with the items in it at an auction where they sell off the possessions of those who are delinquent on payments. In the unit were two Pokemon cards. Looking at Ebay, the first one, "Mew", - same exact card, was listed at $1500! When I took it to a local shop to see what they thought, the employee was first excited and then told me it was worth $3. That is quite a discrepancy so I was hoping for some unbiased opinions as to what the card is really worth. The second card, "mew two" has a hologram foil background to the picture. I look forward to whatever thoughts anyone may have on the matter.
Thanks in advance!