Yes, we do provide you with your own cgi-bin. You may upload your own scripts to it but your scripts must not cause issues with our servers or use too many resources to the detriment of other users.
Make sure your cgi scripts are uploaded using ASCII transfer mode in your FTP client, and CGI scripts must be placed in the cgi-bin folder to be called from other scripts. Your script should also have the permission of 755 set to it.