For a "cheap" key, your local Premium Locksmith should be able to get you a wallet key for chump-change, but the difference is with the cheap key, the metals used are softer, therefore you'll wear down the key at a faster rate and the wearing will leave small, metal shavings in your lock. Thereby, eventually requiring expensive repair work.
$30.00 is pretty cheap insurance...and you'll keep from tearing up the keyway with the cheaper stuff.
GL!