It would be cheaper to get an iPad. You can still host FileMaker using FileMaker Pro or FileMaker advanced and then use WiFi to link in an iPad or iPhone as a client of it. There are limitations and the connection is not encrypted like it would from server, but if low cost is the driving decision factor, this will cost you less than acquiring server just to use your android tablet.
FMS and FM can run on the same machine but it is not the intended use. An iPad will be your quick and easy solution.
You may may want to consider the FileMaker Developer Subscription at $99. This will give you FMS in a low cost test versions and allow you to test how the remote web direct interface will work for you in an android browser. The FDS is limited to one web connection intended For development purposes.
Another option is hosting with a service. Many low cost options available there too.
I suppose a used ipad shouldn't cost too much... worth considering.