Where to get cheap 12V high current lead acid batteries?

[bulkhead]

I need 24V to power two wheelchair motors, and am looking for a low cost solution (hence lead acid batteries instead of NiMH).  The problem I have is that I am looking for a 60amp + continuous current capacity, but a lot of the batteries I see online do not have any specifications other than the amp-hour rating, which doesn't say much about peak current capacity.  From searching around, it seems like I will need AGM or Absorbed Glass Mat lead acid batteries which have lower internal resistance.  Online sites are fine, as well as local solutions (perhaps auto stores for motorcycle batteries?).  Any suggestions/input would help, thanks.

[airman00]

search ebay for wheelchair batteries or UPS batteries ( for power backups, not UPS shipping)

[HDL_CinC_Dragon]

go to a junk yard and find two car batteries and hook them up in series (make sure theyre both good though and as close to the same actual voltage as possible)