"A cashier's check (also known as a treasurer's check, bank check, or teller's check) is a check issued by a bank on its own account for the amount paid to the bank by the purchaser with a named payee, and stating the name of the party purchasing the check (the remitter).
"The check is usually received as cash since it is guaranteed by the bank and does not depend on an account of a private individual or business. Cashier's checks are commonly used when payment must be credited immediately upon receipt for business, real estate transfers, tax payments and the like."
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http://en.wikipedia.org/wiki/Cashier%27s_check
Good points are that you aren't carying cash and the payment is guaranteed (the bank debits or puts a hold on your account when they give you the check) so the seller has no excuse to refuse it. Well... one excuse: they think it is counterfit... but a call to the bank can verify a cashier's check so there is no real risk... and if you don't buy, you take it back to the bank and they credit your account again.
Ride it like you think owning it matters.