If you have an older version of Access, then you can buy the upgrade - ebay has some for $60 to $75.
Or, search ebay for office 2000 pro or professional version - it includes Access. If you have another version of office, you may be able to use the upgrade here, also.
You might consider downloading the free (open source) software suite called OpenOffice. It includes a database program called Base. The drawback is that Base and Access files are not interchangeable (at least not the way that Calc/Excel and Writer/Word are), but if you’re only developing your own simple database, for example to use as a tracking system, this could be a cheap way to go. Go to http://www.openoffice.org/ for details…