Remote Office Connection

Need to connect 3 windows 2000 workstations at a remote site to a windows 2000 server at the main office. The 3 workstations will have Access 2000 on local drive. Need to have access to an Access database on server at main office. Client is non-profit. 56K, DSL (not available), and T1 are not options. Someone suggested putting 3 modems on the server and pooling them. Will I need 3 separate phone lines for these modems? Is there a better way? Client does not want a monthly expense.(56K, T1)