in a pinch I've used Crisco.   Better than nothing.

Seems like I've seen  tire mounting lube in  smaller containers... such as   quart size.. besides the  gallon pail or  5 gallon  bucket.

Dawn  works in a pinch too,   (I used it  'straight' out of it's  container.)   I can't  say it's  the ingredients  in  grease-cutting  Dawn,   or  the  'new'  rubber of  today;   Seems like  there is  some sort of  degradation  of the rubber   that  got  slathered up.    All I know is  when it's  time to dismount,   it's  harder to break the bead   when ever  Dawn  was  used to mount the  tire.      Rims  not in the best of  shape  seem to  rust  a little more aggressively  when  Dawn is  used too.   At least  in my  experience.