I am trying to find out if there is any federal or state
(Pennsylvania) law that will allow me to break a contract without a
penalty if I cancel within 24 hours of signing.
Here is the scenario: I ordered a custom built shed on Sunday at 1:00
PM for around $1,400 and put down a 20% deposit via credit card.  I
was given an estimate of 5 weeks for delivery.  Sunday night I
realized that this shed might actually be a violation of my
homeowner's association rules.  Therefore, I need to cancel the order.
 I notified the shed builder company on Monday morning at 9:00 AM that
I can no longer buy the shed because of these rules that I found out
about.  The shed builder is saying that they will return all but $35
of my deposit and the contract does have a clause saying they are
allowed to charge a "handling fee" if I cancel the contract which I am
allowed per the contract to do for 5 days after signing.
Is there any way that I can get all of my money back?  Is there any
law on my side?  Or is there any other way to handle this?  Any facts
or ideas would be appreciated.

This may be helpful:

Pennsylvania Legal Services: Your Right to Cancel Certain Contracts
http://www.palegalservices.org/Brochures/english/11_Right_to_Cancel_Contract.pdf