The drawback with money orders is that they are easily counterfeited. Even U.S. Postal Service money orders are being counterfeited.

Western Union charges horrendous fees; most serious buyers won't want to add that overhead to a big purchase. $68 to transfer $1000, US to UK, likely similar in the opposite direction, plus a currency conversion fee. If using Western Union, have it sent to an agent and in U.S. dollars.

If PayPal is drawn from a credit card, what's to keep the buyer from going back to the credit card company and disputing the charges?

"If you used a credit card to fund a purchase of goods or services through PayPal, you may have chargeback rights granted by your credit card issuer. Credit card chargebacks, if they apply, can be filed more than 45 days after the transaction, are not limited to funds in the seller’s balance, and cover cases where the goods are not as described by the seller as well as cases of non-delivery.

You can choose to pursue the Buyer Complaint process or your credit card chargeback rights; however, you cannot pursue both at the same time or seek a double recovery. If you initiate a Buyer Complaint claim and, while the claim is pending, you file a credit card chargeback, PayPal will cancel your Buyer Complaint claim, and you will have to rely solely on your credit card chargeback rights.

If you cancel your Buyer Complaint claim or it is denied or results in no refund, you may still be able to pursue credit card chargeback rights. In many cases, your credit card company will allow you to file a chargeback for 90 days or more after the date of the payment. If PayPal resolves a Buyer Complaint claim in the buyer’s favor but the buyer does not receive a full recovery of their payment, and if the time for processing of the claim results in the buyer’s loss of credit card chargeback rights, then PayPal will provide a full recovery to the buyer. "

And here is how it affects the seller:
"When a seller receives a payment through PayPal, if the buyer files an unauthorized transaction claim or a claim under PayPal’s consumer protection programs (a “Buyer Claim”), or if the buyer files a credit card chargeback, a Temporary Hold will be placed on the amount of the payment. If the transaction qualifies for the Seller Protection Policy, the temporary hold will be lifted from those funds.

If the transaction does not qualify for the Seller Protection Policy, PayPal will review the Buyer Claim, including all information provided by the seller, and make a determination. In the case of a chargeback, PayPal will determine whether the chargeback can be disputed with the card-issuing bank. If PayPal disputes the chargeback, the Temporary Hold will continue until the dispute is decided by the applicable card company (Visa, MasterCard, American Express or Discover).

If the seller loses a Buyer Claim or a chargeback dispute and does not qualify for the Seller Protection Policy, the seller will owe PayPal for the amount of the reversed transaction. In the case of a chargeback, sellers who do not meet the requirements of the Seller Protection Policy will also owe a $10.00 USD chargeback fee. PayPal will seek to recover the funds from sellers by debiting their PayPal balance. If there are not sufficient funds in the seller’s PayPal balance, sellers have a choice of reimbursing PayPal by funding their PayPal account or by other means as described in the Payments (Sending, Receiving, and Withdrawals) Policy."

My credit union will take my deposits and post them as available same day under $500, within 2 days for anything drawn on a US bank, or within 10 days for anything global. However, the actual processing time (despite that with computerized systems they could process immediately), money orders and cashier's checks are not guaranteed clear for 14 days after deposit.

The reason I recommend a new, single use bank account is isolation of funds; when you give the information required for a wire transfer, you are giving the same information printed on your checks...your bank name, ACH number and account number. With the independent check printing companies, that's all it takes to have checks printed that draw on your account. Then you have to fight the bank to prove the fraud, and deal with credit bureaus and creditors to try to undo the damage. Far cheaper to use a separate bank account if anything goes wrong, and cheap insurance even if all goes well. As a business owner, I have a savings subaccount for all my ACH transactions, like IRS payroll deposits, that does not draw on the primary account and carries a zero balance until the payment is due and does not have check draw capability.