What I want to use it for is to make copies of paper magnetic cards. The type that you might get from a parking garage for example.
About 30 years ago I wrote some software for devices that used Diebold banking-class motorized magstripe reader/writers. I later worked for a company who used a variety of paper and plastic magnetic tickets and cards (e.g. NYC MTA, Washington Metro, BART, London Underground, something in Brisbane, Singapore, etc.). I even think they did a parking lot system at one point. So I have a general understanding of the recording methods, what might/should go on a stripe, etc.
Beware that paper parking/transit tickets may not use media of the same magnetic coercivity as ABA (ISO/IEC 7811-2) magstripes. Also, while ABA magstripes are F2F encoded there are also MFM encoded stripes out there for purposes that do not need interchange. Track positions from the edge of the card can also be varied. And there are other encoding tricks that can make it difficult for off the shelf equipment to read/modify/write proprietary stripe formats.
An article on attempting to reverse engineer the
NYC MetroCard appeared in "2600: The Hacker Quarterly" some years ago, and this
ancient web page seems to be based on that article. There is certainly
more out there about attempting to
hack the MetroCard and other magstripe card/ticket systems.