Tablespaces

User quotas on all tablespaces

col quota format a10
select username
,      tablespace_name
,      decode ( max_bytes
              , -1, 'unlimited'
              , ceil(max_bytes / 1024 / 1024)||'M'
              ) quota
from   dba_ts_quotas
where  1=1
and    tablespace_name not in ('TEMP');

Report of available free space in tablespaces

Original page
You probably have a problem with the autoextend max_size if column 5 is less than column 8!

set pages 400 lines 132
-------------------------------------------------------
-- free.sql  
--
-- This SQL Plus script lists freespace by tablespace
--------------------------------------------------------

column  dummy noprint
column  pct_used     format 999.9       heading "%|Used" 
column  name         format a19         heading "Tablespace Name" 
column  Kbytes       format 999,999,999 heading "KBytes" 
column  used         format 999,999,999 heading "Used" 
column  free         format 999,999,999 heading "Free" 
column  largest      format 999,999,999 heading "Largest" 
column  max_size     format 999,999,999 heading "MaxPoss|Kbytes"
column  pct_max_used format 999.9       heading "%|Max|Used" 
break   on report 
compute sum of kbytes on report 
compute sum of free   on report 
compute sum of used   on report 

select (select decode(extent_management,'LOCAL','*',' ') || 
               decode(segment_space_management,'AUTO','a ','m ')
	      from dba_tablespaces where tablespace_name = b.tablespace_name) || nvl(b.tablespace_name, 
			 nvl(a.tablespace_name,'UNKOWN')) name,
	   kbytes_alloc kbytes, 
	   kbytes_alloc-nvl(kbytes_free,0) used,
	   nvl(kbytes_free,0) free, 
	   ((kbytes_alloc-nvl(kbytes_free,0))/ 
						  kbytes_alloc)*100 pct_used,
	   nvl(largest,0) largest,
	   nvl(kbytes_max,kbytes_alloc) Max_Size,
	   decode( kbytes_max, 0, 0, (kbytes_alloc/kbytes_max)*100) pct_max_used
from ( select sum(bytes)/1024 Kbytes_free, 
			  max(bytes)/1024 largest,
			  tablespace_name
	   from  sys.dba_free_space 
	   group by tablespace_name ) a,
     ( select sum(bytes)/1024 Kbytes_alloc, 
			  sum(maxbytes)/1024 Kbytes_max,
			  tablespace_name 
	   from sys.dba_data_files 
	   group by tablespace_name 
	   union all
      select sum(bytes)/1024 Kbytes_alloc, 
			  sum(maxbytes)/1024 Kbytes_max,
			  tablespace_name 
	   from sys.dba_temp_files 
	   group by tablespace_name )b
where a.tablespace_name (+) = b.tablespace_name
order by &1
/

If you are stuck on software written last century:

set pages 400 lines 132
-------------------------------------------------------
-- free.sql  
--
-- This SQL Plus script lists freespace by tablespace
--------------------------------------------------------

column  dummy noprint
column  pct_used     format 999.9       heading "%|Used" 
column  name         format a19         heading "Tablespace Name" 
column  Kbytes       format 999,999,999 heading "KBytes" 
column  used         format 999,999,999 heading "Used" 
column  free         format 999,999,999 heading "Free" 
column  largest      format 999,999,999 heading "Largest" 
column  max_size     format 999,999,999 heading "MaxPoss|Kbytes"
column  pct_max_used format 999.9       heading "%|Max|Used" 
break   on report 
compute sum of kbytes on report 
compute sum of free   on report 
compute sum of used   on report 
                                                                                                         
select (select decode(extent_management,'LOCAL','*',' ')
          from dba_tablespaces where tablespace_name = b.tablespace_name) ||
nvl(b.tablespace_name,
             nvl(a.tablespace_name,'UNKOWN')) name,
       kbytes_alloc kbytes,
       kbytes_alloc-nvl(kbytes_free,0) used,
       nvl(kbytes_free,0) free,
       ((kbytes_alloc-nvl(kbytes_free,0))/
                          kbytes_alloc)*100 pct_used,
       nvl(largest,0) largest,
       nvl(kbytes_max,kbytes_alloc) Max_Size,
       decode( kbytes_max, 0, 0, (kbytes_alloc/kbytes_max)*100) pct_max_used
from ( select sum(bytes)/1024 Kbytes_free,
              max(bytes)/1024 largest,
              tablespace_name
       from  sys.dba_free_space
       group by tablespace_name ) a,
     ( select sum(bytes)/1024 Kbytes_alloc,
              sum(maxbytes)/1024 Kbytes_max,
              tablespace_name
       from sys.dba_data_files
       group by tablespace_name
       union all
      select sum(bytes)/1024 Kbytes_alloc,
              sum(maxbytes)/1024 Kbytes_max,
              tablespace_name
       from sys.dba_temp_files
       group by tablespace_name )b
where a.tablespace_name (+) = b.tablespace_name
order by &1
/