I entered into an agreement to purchase 2 I-Pads for $200 each. However, when I called on the day they said they would be back from their trip I was

If you had an agreement to buy the IPads, the seller cannot just back out of it.  However, absent something in writing, it will be difficult for you to prove that you had a binding agreement.  Also, even if you can prove the agreement, you will need to prove that you were damaged by the breach (assuming that the IPads are already gone to the other party and cannot be recovered).  This would mean that you would have to prove that the IPads were worth more than the $200 you agreed to pay for them, in which case you could collect the difference between $200 and what they were worth.  Frankly, it doesn't sound as if the sum at issue is worth the hassle and possible costs (filing fees, etc.) involved, especially since there is no guaranty that you would win.