If you have a US residence, do you also have a US bank account to handle your household expenses?
If so, you are golden.
Using your US address and your US bank account, start a different eBay account on dotCOM. If you have a US credit card all the better. You will need a different email address.
If you buy using that account, you can pay from a US Paypal account and add any US address you like.
Basically, PP allows several addresses to be added to their accounts, but all the addresses must be in the same country where the PP account is registered.
You might be able to add the US PP account to your Canadian eBay account, but the above method will help you remember where stuff was sent.