Buyer asked for my paypal email address. Is this normal?

Buyers are not to see your email address until AFTER they pay!  Do not send it.  If your shipping was to the US only, invoice for a high shipping charge and ignore the request, and file a dispute when he doesn't pay (or ship if he does).

You were supposed to set BLOCKS in your seller account buyer prefs.  Do so, for the future.

 Can I cancel the purchase and relist the item?

Assuming they did not pay ...

If you want your Final Value Fees refunded, and the ability to make a Second Chance Offer, or relist correctly,  you must do one of the following:

1. Complete the Unpaid Item process  (usually preferred)

 or

2. Convince the buyer to agree to a Cancellation Request,

Both options are available in the eBay Resolution Center

Here is a comparison of the timelines, pros, and cons of filing an Unpaid Item (UPI) report versus a Cancellation Request (CR)

http://www.pirsquare.notlong.com/upi_or_cancel.html

Also consider putting the bad  bidder on your Blocked Bidders List.  (Stop back here for more information if you need to learn how to do that).

A great place for quick answers; no waiting, no voting,
"Do It Yourself": eBay Customer Support .